Maybe there are exceptions, but I have noticed a marked pattern - espeed spammers have been way higher on the ladder, and making teams with no espeeders that can consistently win matches is almost impossible.
I also have no Extreme Speeders and never have, and I'm doing pretty decent on the ladder. Aside from Mega Pinsir and friggin' Serperior, I haven't had any particular problems. (That and Gothitelle and Gothorita, but Shadow Tag is banned already, thank everything) I've also never seen more than two Extreme Speeders on any team I've fought, and most times it's just the one -Mega Pinsir. I almost never see anything else run Extreme Speed at all.
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OK here's why I think
Mega Pinsir should be banned, and not Extreme Speed.
Mega Pinsir is the only -ate choice with +2 setup, the only one that naturally breaks 100 Speed, and the only one that natively brings
perfect coverage to the table. If you resist Flying, the possibilities go like this.
types... +2 252 Atk Mega Pinsir Close Combat vs. 252 HP / 252+ Def Regirock: 258-304 (70.8 - 83.5%) -- guaranteed 2HKO after Leftovers recovery
That's the single Physically bulkiest Rock type in the entire game, and it takes abominable damage from Close Combat. While Regirock is a lot more viable in Sketchmons than in Standard, this is still absurd. A more popular choice is, of course...
+2 252 Atk Mega Pinsir Close Combat vs. 252 HP / 252+ Def Eviolite Rhydon: 252-298 (60.8 - 71.9%) -- guaranteed 2HKO
... which takes comparable damage if it's still holding its Eviolite. By the way, did you know Pinsir can learn Knock Off natively? And there's not much reason to run Earthquake alongside Extreme Speed and Close Combat, honestly. Ghost/Rock, Ghost/Electric, and Ghost/Steel are really the only reasons to run Earthquake, and oh wait they all hate Knock Off, especially Eviolite Doublade. (There's no Poison/Rock, Poison/Steel, or Poison/Electric types, so Poison isn't actually a reason to run Earthquake -just Extreme Speed them)
+2 252 Atk Mega Pinsir Close Combat vs. 252 HP / 252+ Def Rhydon: 378-446 (91.3 - 107.7%) -- 50% chance to OHKO
Well, there goes
that check.
types best case scenario, by far, is Mega Aggron.
+2 252 Atk Mega Pinsir Close Combat vs. 252 HP / 252+ Def Filter Mega Aggron: 172-204 (50 - 59.3%) -- guaranteed 2HKO
.... what's that you say? Skarmory is better?
+2 252 Atk Mega Pinsir Close Combat vs. 252 HP / 252+ Def Skarmory: 170-200 (50.8 - 59.8%) -- 89.1% chance to 2HKO after Leftovers recovery
Nope. Takes slightly more damage, actually suffers when hit with Knock Off, its best attacking retaliation involves hurting itself, and it's a lot more afraid of, say, Magnezone than Mega Aggron is.
Doublade is better, except you hit it with Knock Off on the way in and now it's in real trouble. Also it's vulnerable to Pursuit trapping, to boot.
types have exactly one good option: Zapdos. It's legitimately an impressive one, too.
+2 252 Atk Mega Pinsir Knock Off (97.5 BP) vs. 248 HP / 252+ Def Zapdos: 192-227 (50.1 - 59.2%) -- 80.1% chance to 2HKO after Leftovers recovery
Not that scary, given that if you're doing this it's because you're letting Zapdos instagib you with Thunderbolt. So there's a pretty hard counter to Mega Pinsir.
But if you're not talking Zapdos? The next most defensible Electric type not weak to Close Combat is Mega Ampharos. After that you're basically either talking unviable Pokemon or Pokemon you'd be insane to run defensively, leading to stuff like
+2 252 Atk Aerilate Mega Pinsir Extreme Speed vs. 0 HP / 4 Def Thundurus: 258-303 (86.2 - 101.3%) -- 12.5% chance to OHKO
this. (Which is of course an easy OHKO if you've got Stealth Rock up) Oh, also consider
252 Atk Mega Pinsir Knock Off (97.5 BP) vs. 0 HP / 4 Def Thundurus: 161-190 (53.8 - 63.5%) -- guaranteed 2HKO
followed by
252 Atk Aerilate Mega Pinsir Extreme Speed vs. 0 HP / 4 Def Thundurus: 129-152 (43.1 - 50.8%) -- 3.1% chance to 2HKO
In other words, just Extreme Speed, Swords Dance, and Close Combat puts Mega Pinsir in a position to kill almost everything in the entire game, especially if it has hazards support.
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Other Extreme Speed possibilities are just not that impressive. Putting Extreme Speed on a Normal type is, broadly speaking, comparable to Linoone in OU, where it gets
Belly Drum Extreme Speed and nobody cares. Ursaring with Guts-boosted Extreme Speed is easier to get into action, and has better bulk than Linoone before you count the Belly Drum against Linoone, but it actually hits a lot less hard
252+ Atk Guts Ursaring Extreme Speed vs. 0 HP / 0 Def Mew: 216-255 (63.3 - 74.7%) -- guaranteed 2HKO
+6 252+ Atk Linoone Extreme Speed vs. 0 HP / 0 Def Mew: 382-450 (112 - 131.9%) -- guaranteed OHKO
and on top of that its base Speed is a
lot worse, opening a much larger number of Rock, Steel, and Ghost types as counters/checks by virtue of outspeeding it and putting the hurt on it before it gets in a coverage hit. (For that matter, some Physically bulky neutrally vulnerable cases can tank a hit and hit back hard) I just don't see Guts Ursaring as considerably more scary than Belly Drum Linoone, and meanwhile the rest of the meta has also gotten better. The main advantage Guts Ursaring has is having no fear of Will O Wisp, basically. (Admittedly, you can do Guts Belly Drum Ursaring, but then you're just asking to die horribly having done nothing through sheer self-damage)
It's not even possible to get Scrappy Belly Drum Extreme Speed in Sketchmons, which would be legitimately terrifying.
Which leaves the other -atespeeders.
Mega Glalie is held back by being Mega Glalie. Its coverage is awful, its Speed tier is problematic, it's not that bulky, its boosting options are pathetic. I haven't seen anybody complaining about it, and with good reason.
Mega Gard- yeah I'm joking.
Sylveon... still a joke.
Aurorus, which has the valuable niche of not being a Mega. Its Attack is even respectable, and not that much lower than it Special Attack. Its Physical movepool is OK, too. It's also slow, with a tortuously bad typing, meh stats overall, and easily walled by bulky Steel types. The nicest thing I can say about it is that most people will assume Special Aurorous, and so might botch their switchin.
Mega Salamence is already banned.
Which leaves Mega Altaria. Mega Altaria is slower than Mega Pinsir, has inferior coverage (Albeit the advantage of competent Fire Blasts letting it push past Skarmory and, yes, Physically Defensive Mega Aggron [0 SpA Mega Altaria Fire Blast vs. 252 HP / 0 SpD Filter Mega Aggron: 154-183 (44.7 - 53.1%) -- 28.9% chance to 2HKO] if it cares to do so), has substantially worse Attack, and its boosting is Dragon Dance -which is amazing, but not nearly as terrifying in conjunction with Extreme Speed. Its main advantage is more its unpredictability -Mega Pinsir is Physical, the end, whereas I've seen Boomburst Mega Altaria and it's not
terrible- but overall it's
vastly less threatening than Mega Pinsir.
So basically Extreme Speed is only notable in the hands of
-A handful of Normal types
-Mega Glalie
-Mega Altaria
-Mega Pinsir
-And maybe Aurorus
Of these, Mega Pinsir and
maybe Mega Altaria are the only really scary, potentially uncounterable ones.
So I don't think banning Extreme Speed makes sense, because it's Mega Pinsir that's the problem, not Extreme Speed. Note, additionally, that it already gets Feint. You know what would happen if we banned Extreme Speed? We'd start seeing Belly Drum Feint Mega Pinsir as a thing, which has the same priority number and hits almost as hard as Swords Dance Extreme Speed. (About 3/4ths, specifically) No, seriously. (And of course Belly Drum Close Combat is an easy OHKO on pretty much any wall you care to name that isn't Quagsire or Clefable) Bonus points, you can't Protect stall Feint to get Poison Heal turns or the like. We'd also lose the option of checking stuff like Serperior/the legions of crazy setup choices out there with Extreme Speed, which hurts, though that's a relatively minor detail.
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I have no particular opinion on Move Clause. I've never built a team that actually had a given move Sketched more than once, and it's not actually that common on enemy teams in my experience. I don't think a Move Clause would have much of an effect, in practice.