"What can it do that SDLuke can't?"

[Scofield]

I also want to mention that specsluke doesn't necesarrily lure and destroy all of sdscizors counters. ie, gliscor is 2hkoed by a sd bp and can't do jack to scizor. Oddly, skarmory and forretress does wall scizor better. However, even then sdluke destroys those two.

 

[TVboyCanti]

Good Post Lee, and I think its great people want to use specsluke now, but a lot of the walls you say specslukes "breaks", SDLuke does more damage to. I don't see the point of a choicer that only barely 2HKOs it's counterpart's counters even with perfect prediction. Sorry Lee, but Specs Luke is really just a gimmick set comparable to Choice Band HustleTic, a fad created by "OMG Blissey has a special weak!!!1!", and I'm only saying this because Smogon has this supposed policy about competitive battling and identifying what sets are gimmick and what sets deserve to be standard. Your damage calcs prove that this is a gimmick compared to SD.
Psychic vs 216/0 Gyarados = 38.96% - 45.71%
Psychic vs 4/0 Gyarados = 45.18% - 53.01%
+1 LO Extremespeed vs 216/0 Gyarados = 56.36% - 66.66%
+3 LO Extremespeed vs 216/0 Gyarados = 94.27% - 110.93%
max LO Waterfall vs min/min Lucario = 86.52% - 102.12%

Hidden Power [Ice] vs 252/0 Gliscor = 167.23% - 196.89%
Psychic vs 252/0 Gliscor = 53.67% - 62.99%
Shadow Ball vs 252/0 Gliscor = 47.74% - 56.21%
Aura Sphere vs 252/0 Gliscor = 40.11% - 47.18%
+2 LO Ice Punch vs 252/252 Impish Gliscor = 149.15% - 176.27%

Hidden Power [Ice] vs 252/0 Hippowdon = 72.86% - 85.71%
+2 LO Close Combat vs 252/252 Impish Hippowdon = 77.9% - 92.14%

Hidden Power [Ice] vs 252/0 Zapdos = 66.67% - 78.39
+2 LO Ice Punch vs 252/252 bold Zapdos = 89.06% - 105.2%

Aura Sphere vs 252/0 Swampert = 60.40% - 71.04%
+2 LO Close Combat vs 252/252 impish Swampert = 97.52% - 115.09%

 

[Lee]

I did go to extreme lengths in the OP to make it clear that SDLuke is the "better" set. However, what you're saying is a little (actually, it's a LOT) like saying SpecsMence is a gimmick because DDMence is more effective.

Your calculations don't hold much weight here. I've posted calculations showing what SpecsLuke can do from the moment he steps into battle, but for whatever reason you've assumed that SDLuke has an automatic +2 Atk everytime he switches in (in one example you've gone as far as to give him +3 Atk...I've yet to see anyone get off two Swords Dances!).

To be fair, a lot of the damage SpecsLuke causes is against incoming switches though so I guess it's fair to assume that in the same situation, SDLuke could use Swords Dance on that switch. However, the lag caused by taking a turn to stat-up means SpecsLuke fares better against just about all of the Pokemon you listed.

Hidden Power [Ice] vs 252/0 Hippowdon = 72.86% - 85.71%
+2 LO Close Combat vs 252/252 Impish Hippowdon = 77.9% - 92.14%

If you Swords Dance while a healthy Hippowdon switches in, you'll CC for some pretty hefty damage but you WILL lose that exchange. However, if SpecsLuke uses Aura Sphere, HP Ice or even Psychic whilst a healthy Hippowdon switches in, it goes without saying who will win.

+2 LO Ice Punch vs 252/252 Impish Gliscor = 149.15% - 176.27%

+2 LO Ice Punch vs 252/252 bold Zapdos = 89.06% - 105.2%

If the opponent switches in Zapdos or Gliscor, you're forced to make a dangerous decision because there's every chance your flying foe will just outspeed you and OHKO. With the advent of Ice Punch Lucario, it seems a little counter-productive to use Gliscor or Zapdos as a counter unless they're running 280 speed because, as your calcs show, they'll just be OHKO'd if they switch in on an SD (last month, around 40% of Zapdos ran high-max speed, whilst just over 20% of Gliscor did the same...I wouldn't be surprised if that increased this month but that's just speculation). SpecsLuke obviously can OHKO both of them (although Zapdos needs to have taken SR damage).

+1 LO Extremespeed vs 216/0 Gyarados = 56.36% - 66.66%
+3 LO Extremespeed vs 216/0 Gyarados = 94.27% - 110.93%

Who runs 216 HP / 0 Def Gyarados? The only Gyarados' that use that much HP are either BulkyGyara or ResTalk Gyara both of which have shedloads of Defense EVs and none (or minimal) SpD EVs which obviously favors SpecsLuke who can 2HKO an incoming BulkyGyara with SR damage factored in, whereas SDLuke would have to Swords Dance the switch before he can 2HKO a 75% BulkyGyara with Extremespeed (+1 LO ES does 45-53%).

+2 LO Close Combat vs 252/252 impish Swampert = 97.52% - 115.09%

The Swampert calculation has worth, I'll give you that...unlike all the other calcs you gave, if Lucario Swords Dances a switch to Swampert, he's almost guaranteed to win. However, the same could be said for SpecsLuke if he Aura Spheres the Swampert switch as it does as much as 70%.

SDLuke is fantastic yes, but nobody is going to agree with you that he has an easier time against physical walls than SpecsLuke.

Another thing you've given little heed to is the fact that SDLuke can only use three attacks. If you opt for CloseCombat/Extremespeed/IcePunch as you have done in your calculations, you'll be walled by Pokemon such as the Rotom formes, Dusknoir and Cresselia. If you go down the CC/ES/Crunch route you'll be walled by the likes of Gliscor, BulkyMence and Zapdos. SpecsLuke has no such problems (edit; adding this to the op because I like it).

You also haven't gave any mention to the fact that SDLuke is constantly losing 10% of his health and cutting his defences each time he uses his STAB attack although I accept that can often be an afterthought.

I hope that those points, combined with that I said in the OP, convince you that SpecsLuke isn't entirely outclassed by his Swords Dancing bretheren. Or at very least, stop you from comparing him to Choice Band Togekiss. :X

Onto a few other posts;

(You write an awful lot like I do, I've noticed, which I obviously like because I, the mighty Jumpman16, am the best.)

The insecure part of me thinks you're mocking my often excessive use of commas, but I'm definately going to take this one as a compliment regardless. 8)

words about CMLuke

I've never been a fan of CMLuke. He's just a little bit too slow, and CM doesn't do enough to patch up his low SpD. If it was Nasty Plot, there'd be a good set in there but CM has never really cut it for me. Having said that, you two are the second and third good battlers to have claimed to have had success with CMLuke in the past few weeks (the other being Stellar) so I'll have to get round to giving him another go sometime.

words about building a team around SpecsLuke

Honestly, you guys have got to promise to share the results of that with me. I'm still fiddling around to decide how best to incorporate him into a team. The most successful one (got into the standard top 20 within a few days even though I convinced myself I wouldn't actually play Platinum :\) was a rather Stall-esque team that used Pokemon such as Yawn/U-Turn Uxie and a slow Baton Pass Vaporeon to buy Lucario as many free switch-ins as possible. I'd like to see what you guys have got in mind as it's still very much a WIP.

Picture

Hahaha, thanks for that. Great stuff.

 

[Bourbon]

Exactly.

You're giving Swords Dance Lucario a "free" Swords Dance. It doesn't matter if he can 2HKO after a Swords Dance. If he can't OHKO after the boost, he isn't going to win if they can OHKO back!

In other words, Specs Lucario does a hell of a lot more damage over the course of two turns than Swords Dance Lucario does over it's first two turns. After this period, Swords Dance Lucario is more efficient.

IE, look at the Gyarados.

SDluke:

Tyranitar, come back!
Go Gyarados!
Pointed Stones dug into Gyarados.
Gyarados Intimidate cut Lucario's attack!
Lucario used Swords Dance!
Lucario's Attack sharply rose!
--

Lucario used Extreme Speed! (56%)


Specs Lucario:

Tyranitar, come back!
Go Gyarados!
Pointed stones dug into Gyarados.
Gyarados Intimidate cut Lucario's attack!
Lucario used Psychic! (39%)

--

Lucario used Psychic! (39%)
Gyarados fainted!

Also bear in mind that Lucario could (and maybe should!) run Hidden Power Rock, so it can severely hurt Gyarados, Salamence, Zapdos, and Dragonite all with one move. Then one could run Dragon Pulse, or, God forbid... Flash Cannon, to 2HKO Spiritomb and have an answer for Tyranitar without fearing a ghost switchin.

So in short, Swords Dance Lucario deals more damage over a long period of time, while Specs Lucario packs much more initial power. Two Choice Specs Aura Spheres does only 10% less than a Swords Danced Close Combat... so the power difference is only noticable on the third turn.

 

[Kagster123]

Specsluke can also kill Weezing, while SDLuke can't deal with it. There's nothing worse then SD'ing on the switch only to have a Weezing come in and force you out.

I can't run any calcs at the moment, but does an Adamant LO +2 Ice Punch OHKO Nidoqueen? If not that's another pokemon Specsluke is better off fighting.

 

[Bourbon]

With Stealth Rock up, SD Lucario has a 41% chance of OHKOing Nidoqueen with +2 LO Ice Punch. Without it, it has a 2.56% chance.

Obviously without Ice Punch it doesn't have any hope but that goes without saying.

 

[Taylor]

Honestly, you guys have got to promise to share the results of that with me. I'm still fiddling around to decide how best to incorporate him into a team. The most successful one (got into the standard top 20 within a few days even though I convinced myself I wouldn't actually play Platinum :\) was a rather Stall-esque team that used Pokemon such as Yawn/U-Turn Uxie and a slow Baton Pass Vaporeon to buy Lucario as many free switch-ins as possible. I'd like to see what you guys have got in mind as it's still very much a WIP.

No problem whatsoever. ;]

Unlike your idea, my method was to build a team (that was offensively-based) that fed of Lucario's unexpected OHKOs and 2HKOs; which would benefit the majority of my team, if not all. With Uxie and Vaporeon, it seems to me that you're supporting Lucario more than Lucario is supporting your team. I know that what I just said may seem nonsensical, but I do plan to assemble a creation where Lucario intentions are to suprise the opponent, which hopefully opens up options for other sweepers in my team.

 

[TVboyCanti]

They're all +2 since I'm assuming that all those targets would be switching in to Luke to counter it (that's why they're called counters right?) as he SDs.

Against Gyarados Luke could get 2 SDs since it has a solid 86% chance to survive a maxed out waterfall from Gyarados, if it's full health. Okay that's scenario is unlikely, but a lot Dosers would predict the switch and use DD or maybe even Stone Edge, which could give you the extra SD to score a KO. I realize that I messed up the gyarados evs, using a bulkydos without def evs. Against the new standard Gyara, Extremespeed does 65-77% with One SD, a ko if gyara has switched in twice on stealth rock, and guranteed 109+% if your gutsy enough to SD twice.

Anyway I didn't mean to come of as offensive or belittling, though I guess calling the set a gimmick probably sealed my fate there, sorry about that. I think Taylor really nailed CSpecslucs purpose as a way to set up another sweeper by punching through a problem wall. This is a battle tactic created in DP due to the reliance on typing instead of stats, and being an ADV gen battler I am not adept at, so I didn't see it at first. When you said "Wallbreaker" in your OP, I was thinking about stuff like MixApe, Mixmence, and ChainChomp, which are the stereo typical wall breakers.

If the purpose of this thread was to promote Luke going special instead of SD, I'm curious what your opinions are on CMluke. I think that CM luke would be the way to go for a special luke, since it can hit harder with a Life Orb (even if it goes Timid) and doesn't rely on prediction so much. The three moveslot syndrome would hurt it's coverage, but that would really just be a matter of whether you have problems with Cress/Dusknoir or with Bulky fighting types.

Again, I apologize for my arrogance.

 

[remlabmez]

Not going to lie, saw a specs luke a few days ago and it really threw me off gaurd. It has a really nice suprise factor. I think you should show calcs of a specs vacuum wave to heatran. Who is a very common revenge killer of lucario. It might be something I will try out whenever I am bored. But it seems like you need to scout your opponent well and predict which might take some practice to perfect using specsLuke to its full potential.

 

[Cynthia]

On the matter of Gyarados, Earthquake is a very common move and that will OHKO Lucario. I would never assume +3 atk personally.

As for the moveslot syndrome on CM Luke it isn't really an issue, since you don't really need Psychic. The pure fighters really don't have the special defense to take boosted Aura Spheres, leaving Toxicroak and Heracross as the resists. They both have pretty medicore special defense, especially Toxicroak. Poison types could theoretically wall this set, but the Nidos are hit by HP Ice, Weezing's Spdef sucks, Tentacruel can't hit back, etc. Psychic would be nice for Muk I guess, but frankly there aren't too many Muks in OU, the only main OU counter to this set is Gyarados.

 

[Bourbon]

Hidden Power Rock is looking more and more impressive all the time. Since Garchomp is gone, the main reason for Hidden Power Ice over Hidden Power Rock is gone. Not to mention that it deals near fatal damage to Salamence, Gyarados, Zapdos and more, something that Hidden Power Ice cannot boast, as Gyarados gets away with a mere 70 power from it.

Fighting and Rock also has excellent coverage, walled only by Claydol, Toxicroak and a couple others. But Lucario's other boosted attacks deal with these pokemon nicely. I am convinced that the new Specs Lucario set should be Aura Sphere / Shadow Ball / Hidden Power Rock / Dragon Pulse

Vacuum Wave could go in the last slot, as Rock/Fighting and Dark/Fighting already have superb coverage. Flash Cannon is an interesting option though. It's "Super Effective" type coverage is pretty terrible, but it provides an answer for Spiritomb, and also allows you to smack around Tyranitar without locking into a Fighting attack. I mean, Metagross can get away with Meteor Mash, can't it? I don't see why a decent move like Flash Cannon should be ignored.

 

[cim]

They're all +2 since I'm assuming that all those targets would be switching in to Luke to counter it (that's why they're called counters right?) as he SDs.

And when did Lee ever say this wasn't the case? he clearly showed that you didn't get OHKOs, and if you don't OHKO Lucario will probably die. However, with Specs you can hit on the switch you only need 2HKOs. He probably assumed this was obvious to you.

Against Gyarados Luke could get 2 SDs since it has a solid 86% chance to survive a maxed out waterfall from Gyarados, if it's full health.

Gyarados's Earthquake is a guaranteed OHKO, and you shouldn't rely on a misprediction to "beat your counters" or whatever, not to mention the whole 216/0 point.

Hidden Power Rock is looking more and more impressive all the time. Since Garchomp is gone, the main reason for Hidden Power Ice over Hidden Power Rock is gone. Not to mention that it deals near fatal damage to Salamence, Gyarados, Zapdos and more, something that Hidden Power Ice cannot boast, as Gyarados gets away with a mere 70 power from it.

Fighting and Rock also has excellent coverage, walled only by Claydol, Toxicroak and a couple others. But Lucario's other boosted attacks deal with these pokemon nicely. I am convinced that the new Specs Lucario set should be Aura Sphere / Shadow Ball / Hidden Power Rock / Dragon Pulse

Dragon Pulse is pretty meh here, as Kingdra and Flygon really don't like boosted Aura Spheres anyway.

As for a Steel move, it sounds like Spiritomb is the only reason you'd ever use it. Steel hits basically the same things as Fighting coverage-wise and Water is a horribly common type that resists it.

Vaccum Wave on the other hand is completely awesome, so everyone should always use it.

On the matter of Gyarados, Earthquake is a very common move and that will OHKO Lucario. I would never assume +3 atk personally.

As for the moveslot syndrome on CM Luke it isn't really an issue, since you don't really need Psychic. The pure fighters really don't have the special defense to take boosted Aura Spheres, leaving Toxicroak and Heracross as the resists. They both have pretty medicore special defense, especially Toxicroak. Poison types could theoretically wall this set, but the Nidos are hit by HP Ice, Weezing's Spdef sucks, Tentacruel can't hit back, etc. Psychic would be nice for Muk I guess, but frankly there aren't too many Muks in OU, the only main OU counter to this set is Gyarados.

The issue was never type coverage (although contrary to what you've said Heracross has impressive Special Defense), but rather speed of setting up, which CM Luke has problems with. Also, the Special Defense sucks (I don't understand how Tentacruel can't hit back with unresisted STAB Surf from a decent Special Attack). CM Luke apparently can't "tank" nor "sweep" because of the low defenses andlow set up speed.

Oh by the way I don't know why Psychic is ever used on Lucario except for like Tentacruel I guess. Seems kind of pointless.

 

[Marisa Kirisame]

I'd much prefer rather Hidden Power [Ice] over Hidden Power [Rock] as it allows you to go for that nice instant surprise kill (because people expect the Swords Dance variant) on any Gliscor or Salamence that switch in even though you miss out on Gyarados.

Why would you use Shadow Ball over Dark Pulse except for Heracross, you get coverage on normals and you can get some lucky flinch.

Yeah... Vacuum Wave... always! :D

Dragon Pulse is mainly for type coverage and since Hidden Power [Ice] can already OHKO all the dragons...

 

[Fiskebollen]

Dragon Pulse is mainly for type coverage and since Hidden Power [Ice] can already OHKO all the dragons...

See the smurf on Kingdra's face?
Yeah, that blue thing is laughing at your feeble attempt at dealing damage with HP ice.
HP ice will deal more damage to the other dragons though...

 

[Cynthia]

The issue was never type coverage (although contrary to what you've said Heracross has impressive Special Defense), but rather speed of setting up, which CM Luke has problems with. Also, the Special Defense sucks (I don't understand how Tentacruel can't hit back with unresisted STAB Surf from a decent Special Attack). CM Luke apparently can't "tank" nor "sweep" because of the low defenses andlow set up speed.

Oh by the way I don't know why Psychic is ever used on Lucario except for like Tentacruel I guess. Seems kind of pointless.

I'm getting tired of you disagreeing with every post I make. Heracross's Special Defense is not what I would call impressive, 80/95, and he almost never runs hp or special defense. Timid Lucario is fairly fast, enough to sweep IMO, and Vacuum Wave is an option for priority. And yes, Tentacruel's Surfs are normally fairly damaging, but after a CM it does relatively little. I've actually tested this set, while you most likely have not, yet you try and argue with me anyway.

 

[EvilBob]

Hera only takes 54.30% - 63.91% even after a CM from Shadow Ball, and only 36.42% - 43.05% if unboosted with LO, so yeah, his special defense isn't terrible or anything.

The smogon standard Tentacruel deals Damage: 46.26% - 54.45% before CM, Damage: 30.96% - 36.65% after the first, Damage: 23.49% - 27.76% after the second. It's not much, but considering Luc needs 3 CMs to be able to 2HKO. Assuming you CM on the switch, CM twice more, and then 2HKO while Tenta spams Surf, you'll be taking an average of 83% including the LO damage. So yeah, you'll win (assuming no crits, which Tenta has more chances for), but not with enough life to really continue sweeping.

Weezing is 2HKO'd by Shadow Ball after a CM, but the Fire Blast you would likely take will deal 48.75% - 57.30%, so you'll be taking a little over 70% after two LO recoils.

Basically I can see this set having some use, but CM doesn't really compare to NP or SD for setting up. Even after 1 CM it still needs to rely on 2HKOs on a lot of pokemon, and even with the +1 SpD, it's still not that durable, and is easy to wear down, especially through LO recoil.


On topic for SpecsLuc, I've been really liking the Aura Sphere/Shadow Ball/HP Rock/Vacuum Wave set. Dragon Pulse doesn't seem really needed, outside of a safe option to take out Mence while hitting anything that takes neutral damage for 90 BP instead of just 70. Vacuum Wave gives a nice priority option, although be careful on attempted scarftran revenges, as it only deals 60.19% - 70.68% to 4/0 Heatran. HP Ice vs HP Rock seems to largely depend on how much you care about Gliscor, which depending on your team might be a concern (I really don't care about it right now myself). With Timid Ice Punch Lucs lurking around now, there's always the threat that anyone that's willing to switch in a Gliscor on you may have it EV'd to out speed you.

 

[Cynthia]

For Tentacruel it was in reference to Tentacruel as a counter, so you get to to start with 1 CM. And as I said, the damage output's pretty low after that.

Really you shouldn't keep any Lucario in on Hera unless you have already SD'd and are carrying Extremespeed, since most Heracross are ScarfCross versions, though choice Hera isn't a horrible matchup for Lucario as Hera's moves other than CC are usually 4x resisted.

 

[MetaNite]

SD Luke is a sweeper, Specs Luke is a wall breaker. He's going to be switching a lot, while SD Luke gets one chance.

As far as wall breakers go, there are some better: Infernape. Switch attacks, Grass Knot Gyara, though Lucario has different coverage and specific advantages.

 

[Bentendo1]

One thing you forgot to add was that many Heracross counters overlap with Lucario's counters, so SpecsLuke can act as a lure for Heracross as well. It can also work vice-versa, with Heracross Pursuiting that Calm Blissey or Spiritomb.

 

[cim]

I'm getting tired of you disagreeing with every post I make. Heracross's Special Defense is not what I would call impressive, 80/95, and he almost never runs hp or special defense. Timid Lucario is fairly fast, enough to sweep IMO, and Vacuum Wave is an option for priority. And yes, Tentacruel's Surfs are normally fairly damaging, but after a CM it does relatively little. I've actually tested this set, while you most likely have not, yet you try and argue with me anyway.

I don't quite understand why you implied that I'm arguing against you for any personal reason, or why you think that I'm arguing against you for the sake of it. I just happen to disagree with you in this instance, no need to make it personal.

I don't think you've fought CM Lucario versus Heracross, as you're greatly misunderestimate his Special Defense (He survives even some STAB Air Slashes from 0 SAtk Crobat, for example). Heracross can easily survive a CM Shadow Ball and OHKO right back, shutting down CM Lucario's sweep.

I indeed have tested CM Lucario, and the objections in my post were at least at the time completely valid.

 

[Game Freak201]

I used to run a MixCario at one time. At the time I had a really fun time of bluffing as either a BandCario or SpecsLuke and then killing off a physical or special wall to open up a sweep.

 

[Lee]

Oh by the way I don't know why Psychic is ever used on Lucario except for like Tentacruel I guess. Seems kind of pointless.

Kinda, yeah. I ran Psychic over Vacuum Wave for a bit mostly because I figured Vacuum Wave would be way too predictable and being stuck in a 60BP move resisted by big threats like Salamence, Gyarados and Gengar would suck (plus I already had a few priority attacks elsewhere in the team). It was really useful against bulky fighters like I mentioned in the OP, and it's always nice to have a move that hits Heracross since he's a decent switch-in to SpecsLuke (especially if you use Dark Pulse over Shadow Ball). Tentacruel too obviously. Honestly, I found that I was only using it once every 5 battles (estimate)...I've concluded that it's massively inferior to Vacuum Wave but it might be worth the odd look.

Why would you use Shadow Ball over Dark Pulse except for Heracross, you get coverage on normals and you can get some lucky flinch.

Well, the only popular Normals atm are Blissey, Snorlax and Togekiss all of whom will be taken shit damage from Dark Pulse anyway. Flinch isn't that great either since you'll probably be hitting Ghosts/Psychics on the switch meaning, unlike Shadow Ball, you can't benefit from the secondary effect.
Furthermore, Shadow Ball does have -slightly- better coverage than Dark Pulse as it hits Gallade and Medicham for super-effective damage whereas Dark Pulse only nabs Girafarig (who is OHKO'd by Aura Sphere anyway and well...is Girafarig).

Dragon Pulse is pretty meh here, as Kingdra and Flygon really don't like boosted Aura Spheres anyway.

Indeed, Aura Sphere OHKO's them both after SR.

Against Gyarados Luke could get 2 SDs since it has a solid 86% chance to survive a maxed out waterfall from Gyarados, if it's full health.

And then you'll die from Life Orb. :(

Vacuum Wave gives a nice priority option, although be careful on attempted scarftran revenges, as it only deals 60.19% - 70.68% to 4/0 Heatran.

Yeah, I love Vacuum Waving Heatrans. It's probably worth noting that some Heatrans run Naive in order to power up their Explosion which allows you to do a little more damage (not that that's particularly useful because by the time you've found out Heatran has Explosion there won't be anything left to Vacuum Wave but you get my point). It also nails those Jolly Mamoswines and has a 54% chance of OHKOing them after they've taken SR damage.

 

[RaikouLover]

I Love specs Lucario... Aura Sphere, Hidden Power Rock, Shadow Ball, Flash Cannon / Vacuum Wave. Flash Cannon isn't a terrible option since it is STAB and will hit shit harder than a brick if the opponent doesnt resist it. Vacuum Wave is just so awesome though.

 

[Lee]

Flash Cannon isn't a terrible option since it is STAB and will hit shit harder than a brick if the opponent doesnt resist it.

Flash Cannon sounds like a decent prediction aid thanks to it's ability to hit a lot of things for neutral damage. Say you're up against a slightly weakened 252/0 Tyranitar but your opponent still has Gengar and Salamence in the wings. So what do you do? Aura Sphere and risk giving a free switch to Gengar? You could Shadow Ball or HP Ice...but what if Tyranitar doesn't switch?

Flash Cannon would be useful in such a situation since it effectively removes the need to predict at all. Flash Cannon deals heavy damage to the aforementioned Tyranitar (65-77%), whilst also OHKOing the potential Gengar (95-113%) and Salamence (71-84%) switch-ins (with SR as perusual).

Beyond a situation like that (and Shuckle heh), I don't think Flash Cannon is that great. It'd be third in the pecking order after Vacuum Wave and Psychic imo.

 

[Bourbon]

Psychic? You've got to be kidding... I mean, it hits Poison types that resist Fighting. Big deal, IMO. The only OU Poison types are Tentacruel and (maybe) Crobat. Tentacruel has no way of recovering, and while it would get annoying after a while, it's in no way a real threat to Lucario. Crobat is smacked around by Hidden Power Ice or Rock.

I would choose Vacuum Wave or Flash Cannon over Psychic. Flash Cannon is good because most of the Fighting resists do not resist Steel, such as the aforementioned Salamence and Gengar. Don't forget it's your only chance of 2HKOing Spiritomb. It also hits Heracross (who was brought up many times) for reasonable damage.

The biggest beef people have with Specs Lucario is "it's too hard to predict with" but with a powerful move like Flash Cannon, which hits a great deal of pokemon for neutral damage, it really helps out a lot.