Intro
Reading over this I got quite disheartened in seeing that the general feeling swayed towards keeping Hoopa-U around, so I figured I'd voice my opinion on it, despite the fact this'll probably go ignored because we want to "give the meta time to settle."
Anyway, I was looking over how I should go about this without being ignored, so I'll center this plead for mercy around "
1.The Pokemon creates an auto-win condition against many types (3 is an absolute minimum)."
The unpredictability of Hoopa is just a thing I'd mention, I don't see it as a condition so it's probably irrelevant, but I'd just like to point out that when you see the thing, you don't have a clue if it's going to be Scarf, Life Orb, or any of the other still viable sets like Band, Assault Vest or Specs, which combined with the fact that you can't really risk it being scarfed, makes Hoopa-U certainly worth a look at, even if the "meta hasn't settled yet".
So go through 3 poor types which this thing utterly rips the souls of into tiny little pieces. (Dramatic I know but you'll probably get bored during all this. But please read it V_V)
Electric
Yes I know this section is larger than the other two types, but obviously I can talk more about the type I main and well this takes more explaining as to why Hoopa-U crates an auto win situation)
(Surprise surprise), Electric is a type I strongly feel (and know from experience) that Hoopa-U effectively creates an auto-win condition against. Hoopa-U's "poor physical bulk" is something often commented on, maybe to sort of take away from it's ridiculous and unpredictable wall-breaking power, but more to the point, Electric is a type quite scarce in the physical attacker department, usually only having 1 per team, so considering that Hoopa-U has a nice and tasty 130 base special defense, the fact you probably can't kill it, (that's if the opponent gives you the chance to), isn't even where the problems begin.
The chances are that you're not going to be in with your physical attacker when this thing appears. And then the problem comes that you really don't know what it's going to do. And if you're lucky enough to actually have your physical in, you can't risk it being scarf, because then your physical attacker dies, but if it's not scarfed, one of your walls dies. And considering you're up against Psychic or Dark, hardly favorable match-ups for Electric, you're going to want all the mons you can have, and preferably keep your walls around too because once a wrong play is made with Hoopa and the wrong pokemon dies, it's game over.
Let's say you're lucky enough to have your.. scarf electivire in on Hoopa, one of the only viable scarfers for electric that can really touch the thing.
252 Atk Electivire Wild Charge vs. 0 HP / 0 Def Hoopa: 214-253 (71 - 84%) -- guaranteed 2HKO
252 Atk Hoopa Night Slash (100BP) vs. 0 HP / 0 Def Electivire: 265-313 (91 - 107.5%) -- 50% chance to OHKO
(This is assuming the best case scenario, that Hoopa-U is also scarfed, and Electivire hasn't sustained any prior damage, particularly from hazards, which aren't the easiest to keep of the field for electric, namely against dark where Tyranitar is a free switch in against Zapdos, and then I could go on about sandstorm damage too but w/e)
What a shame. You didn't kill it. And now it can just get a nice free kill any time it comes in. Not to mention if this is on a Dark team, the possibility of Umbreon can pass a wish to it, and although it may be difficult to pull off, you get the idea that the team support is certainly there for it, heal bell being a thing too, also on Mew for psychic.
Here's some calcs to show how little Electric can do to Hoopa-U... (Once a mon has already died to it and you can bring something in)
And then there's ones after to show what Hoopa-U does in return...
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252 Atk Hoopa Night Slash (100BP) vs. 108 HP / 0 Def Magnezone: 169-201 (54.8 - 65.2%) -- guaranteed 2HKO
252+ SpA Choice Specs Magnezone Thunderbolt vs. 0 HP / 0 SpD Hoopa: 193-228 (64.1 - 75.7%) -- guaranteed 2HKO
This is the most powerful special attacker electric teams really have... So the important point in this one, is that your Magnezone is dead. Say, against psychic, that's one of your only ways of killing Mega Gardevoir gone. It's one of your only ways of breaking through mew gone. And it's a sturdy gone that could be used to deal large team any mon on the team, but instead it's wasted dealing damage to Hoopa-U which isn't even dead. The situation against dark is worse, with Magnezone likely being your only mon who can hit the Tyranitar/Mandibuzz core for supereffective damage, and also take a hit from +2 Bisharp, which is a threat of it's own for electric. So if you lose Magnezone dealing damage to Hoopa-U, it's done what I like to describe as creating an easy win situation, not through sweeping as such, but just dealing such damage that you can't prevent to the team, that it makes the match near impossible to win afterwards.
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-1 252 Atk Hoopa Night Slash (100BP) vs. 0 HP / 4 Def Mega Manectric: 153-180 (54.4 - 64%) -- guaranteed 2HKO
252 SpA Mega Manectric Thunderbolt vs. 0 HP / 0 SpD Hoopa: 121-144 (40.1 - 47.8%) -- guaranteed 3HKO
Your pivot and scouter is dead. It didn't even deal 50%...
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252 Atk Hoopa Night Slash (100BP) vs. 0 HP / 0 Def Thundurus: 255-301 (85.2 - 100.6%) -- 6.3% chance to OHKO
252 SpA Life Orb Thundurus Thunderbolt vs. 0 HP / 0 SpD Hoopa: 149-177 (49.5 - 58.8%) -- 99.6% chance to 2HKO
The Thundurus calc is quite irrelevant. Thundy is almost certainly going to have sustained prior damage, either from its Life Orb, its often need to enter the field in order to cripple attackers with prankster twave or of course hazards, which are almost certain against dark due to the Tyranitar pressure on Zapdos.
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252 Atk Hoopa Night Slash (100BP) vs. 252 HP / 0 Def Mega Ampharos: 184-217 (47.9 - 56.5%) -- 86.7% chance to 2HKO
252+ SpA Mold Breaker Mega Ampharos Dragon Pulse vs. 0 HP / 0 SpD Hoopa: 145-172 (48.1 - 57.1%) -- 92.6% chance to 2HKO
Dead. Hoopa-U can do this for fun all day, after chip damage or any prior damage in general from threatening team mates which it certainly has on the types Dark and Psychic.
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Now here comes some more important calcs, onto the Rotom and Zapdos core for electric, which is necessary for the player to keep alive for alive for as long as possible in a game, being the main two mons that are switch ins for anything. And the important part of this, is that you don't know if this hoopa is going to be special or physical, so you literally have to guess, and that's where the game just becomes unfair.
Assuming you guess correct, and go the correct wall:
252 Atk Hoopa Night Slash (100BP) vs. 248 HP / 252+ Def Rotom-W: 132-156 (43.5 - 51.4%) -- guaranteed 3HKO after Leftovers recovery
252 Atk Hoopa Night Slash (100BP) vs. 252 HP / 252+ Def Zapdos: 153-181 (39.8 - 47.1%) -- guaranteed 3HKO after Leftovers recovery
Considering you just dodged a bullet and guessed correctly, that's too much damage, and it's just unfair. Especially considering that neither Zapdos or Rotom can really do anything in return, with both types offering heal bell support of any status attempts.
Now let's assume the (more likely, and almost certain at one point during a game) scenario that you guess wrong.
252 Atk Hoopa Night Slash (100BP) vs. 252 HP / 0 Def Zapdos: 219-258 (57 - 67.1%) -- guaranteed 2HKO after Leftovers recovery
252 Atk Hoopa Night Slash (100BP) vs. 248 HP / 0 Def Rotom-W: 180-213 (59.4 - 70.2%) -- guaranteed 2HKO after Leftovers recovery
252 SpA Hoopa Dark Pulse vs. 248 HP / 0 SpD Rotom-W: 153-180 (50.4 - 59.4%) -- 80.9% chance to 2HKO after Leftovers recovery
252 SpA Hoopa Dark Pulse vs. 252 HP / 0 SpD Zapdos: 175-207 (45.5 - 53.9%) -- 2.3% chance to 2HKO after Leftovers recovery
The chances are quite irrelevant considering the almost certainty of either hazards being up or there being prior damage. So that's it. One of your walls goes down, and if you choose to save it is effectively useless as a switch in due to the health it's left at. Quite frankly, it's game over for electric.
(For Electric) To conclude, Hoopa-U creates an auto-win situation against electric, making it near impossible to win, due to its unpredictability, electric's little ability to return meaningful damage to it without losing a number of mons (so that you can't beat your opponent) and the fact that it breaks the team's defensive core so that your opponent can just use other team members to easily go on to beat you.
"Don't worry, we can run Scarf U-Turn Thundurus!".... There's so much centralization required for electric to be able to deal with Hoopa to the point where your team is just beat by something else instead. Please don't claim that you can prankster twave it, you're forgetting that something has to die to bring thundy in on it, and even then any reasonable player will simply switch out, and even then (again) there is heal bell support on both types.
Ghost
Granted, I don't feel an explanation is needed for this, but the less places people can pick holes in this the better, considering that's all that is going to happen.
So basically whenever Hoopa-U appears vs ghost... somethings dead. And almost everything really. The only real thing that can kill it with being if you're lucky enough to pull a destiny bond off.
252 Atk Hoopa Night Slash (100BP) vs. 252 HP / 0 Def Jellicent: 510-602 (126.2 - 149%) -- guaranteed OHKO
252 Atk Hoopa Night Slash (100BP) vs. 0 HP / 0 Def Gengar: 576-680 (222.3 - 262.5%) -- guaranteed OHKO
252 Atk Hoopa Night Slash (100BP) vs. 252 HP / 0 Def Golurk: 458-542 (119.8 - 141.8%) -- guaranteed OHKO
It's nice putting OHKO calcs up but it's all self explanatory, that Hoopa can literally rip through almost any mon on a ghost mono, and it doesn't even need to be played with skill is what's the sad thing. The important calcs are with Mega Sableye and Aegislash.
252 Atk Hoopa Night Slash (100BP) vs. 252 HP / 0 Def Aegislash-Shield: 270-318 (83.3 - 98.1%) -- guaranteed 2HKO after Leftovers recovery
252 Atk Hoopa Night Slash vs. 252 HP / 252+ Def Mega Sableye: 118-139 (38.8 - 45.7%) -- guaranteed 3HKO
Basically, I'm just going to say that these two mons living is irrelevant. Not only because this is assuming the best case scenario for them, no LO and a physical set, but because Psychic and Dark both have ways to gain prior damage on both these mons, also through hazards, with Ghost not really having a single Defogger.
There's absolutely no dispute that when a ghost players sees a Hoopa-U they might as well just forfeit. I just want to say that it's not like any other unfavorable matchup. Look at Electric vs Dragon, sure it's ridiculously out of your favor, but at least you still have hope. If you make every play right, you can make it a really close game. But this isn't like that. Using Hoopa-U, a player can effectively "click the win button". And that's what's sad. Nothing on the type can really one shot it, and sure there are sashes and what not, but all we're doing by "letting the meta settle" is allowing people to become better at using Hoopa-U, making it more and more deadly. Anyway moving on.
Psychic
Certainly not the only poor type in the situation of no switch-ins. It makes the Psychic v Psychic comparable to the Dragon vs Dragon situation with Mega Altaria. Nvm... I'll get on with some calcs.
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252 Atk Hoopa (100BP) Night Slash vs. 252 HP / 252+ Def Slowbro: 258-306 (65.4 - 77.6%) -- guaranteed 2HKO
4 SpA Slowbro Scald vs. 0 HP / 0 SpD Hoopa: 69-82 (22.9 - 27.2%) -- 53.8% chance to 4HKO
If you're somehow not switching in on this with Slowbro, scald effectively does nothing and even if you're lucky enough to get the burn there is heal bell support, not to mention both Psychic and Dark both certainly have ways of killing slowbro, so the player doesn't even need to risk it. Also if you want to twave it, hoopa still outspeeds if it's scarf....
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252 Atk Hoopa (100BP) Night Slash vs. 252 HP / 0 Def Mew: 384-452 (95 - 111.8%) -- 68.8% chance to OHKO
Sure some Mews run defensive investment... but prior damage and hazards are always there.
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252 Atk Hoopa Night Slash (100BP) vs. 0 HP / 0 Def Mega Gardevoir: 271-321 (97.8 - 115.8%) -- 87.5% chance to OHKO
252 Atk Hoopa Night Slash (100BP) vs. 0 HP / 0 Def Mega Medicham: 219-258 (83.9 - 98.8%) -- guaranteed 2HKO
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I could talk about no switch ins more but it doesn't really prove any more. All that will be used in it's defense is:
252 Atk Victini U-turn vs. 0 HP / 0 Def Hoopa: 384-456 (127.5 - 151.4%) -- guaranteed OHKO
Now I'd just like to talk about this. It's one thing that not every Psychic mono wants to run Scarf Victini but I won't really call it centralization considering it's a hugely viable and popular set anyway. Regardless, this is assuming the opponent for some reason lets you U-Turn their Hoopa-U. The more likely situation is that a Mandibuzz or Slowbro comes in and you simply get rock helmet damage.
Sure this gives you switch initiative, but the fact remains that you can't trade the kills when you're using psychic. Scarf Vicitini/Jirachi is the only thing that Hoopa-U really can't be sent out on, and because of that you're always going to be behind on the kill count, and Hoopa being able to one shot almost your whole team doesn't really help... Psychic Vs Dark is difficult as it is, despite Mega Gard and Medicham providing some hope, Hoopa-U just removes this completely, making the game effectively an auto-win. I'd just like to bring up again then people will only get better at using Hoopa-U, making the struggling types' match ups not just inbalanced, but more like impossible.
Conclusion (Please don't just skip to this(I know that's what everyone will do))
Nearly no switch-ins. Don't use the Mega-Heracross comparison please, because unlike it, Hoopa can run scarf making it quicker, or Life Orb making it even more powerful. And because of this, combined with the unpredictability caused by it and the "can't take risk" of the scarf potential, it creates auto win situations against these 3 types, and if played correctly can certainly do the same against others.
People will only become better at using Hoopa-U, and the fact it can run hugely powerful physical or special sets make it too much for the metagame in my opinion. Against a large number of types, whenever it hits the field it can rip a whole in a team, forcing a player to lose a mon just to find out, or even be able to guess what set it is running. And the mon they've lost, in a large number of situations will cause them to lose the game, simply because they can no longer deal with the hoopa set, or it's team members.
It creates an auto-win condition against Electric, Ghost, and Psychic. These are just 3 hugely vulnerable types. It's not nice to lose a game when you're not at all at fault, and it's not fair to have to rely on a guess or an opponent misplaying just to stay in the match.
I see an argument about Hoopa-U being weak to common priority. Well not all types have the luxury of this common priority. There's also the point that the Hoopa-U user certainly isn't prevented from switching out... Which applies again when it is claimed that "it can easily be revenged". You can just switch out Hoopa-U... and go into one of your reliable walls in Slowbro, Mew, Tyranitar, Sableye or Mandibuzz. Barring Bug and Fighting, I don't see many types who have more than 2 mons on a team who can actually handle the monster without dying. Team support is certainly there on both types. Psychic and Dark both having strong defensive cores, and access to Heal Bell.
I would say tl;dr, but I'd rather people actually read this post before picking holes in it and making it irrelevant.
This is more of a plea for mercy, but
please at least suspect Hoopa-U, certainly on Psychic, and certainly think about it on Dark.
(Don't forget this is all technically opinion, don't hate me too much for it)
P.S. On other matters, I'm in favor of an global Altarianite ban, but pretty neutral on Genesect, Pinsir, and Mega Sableye, and because I don't want to have to write another post like this, I'll just say I'm reasonably neutral on Zard X too.