I'm actually not sure if anybody will use it. Going mega obviously means no Acro builds, and it doesn't get anything stronger than Aerial Ace on either side (not counting Fly, obviously).
Actually, see the below set. You bet you'll see it.
It might not be broken, but does hit hard, even considering that there's one stone it'll likely carry:
Archeops @ Aerodactylite
Ability: Defeatist -> Tough Claws
Stats: 75/170/85/122/85/130 (I don't usually highlight stuff, but you can see the potential here)
EVs: 4 HP/252 Atk/252 Spe
Jolly or Adamant Nature
-Head Smash/Stone Edge/Rock Slide
-Aerial Ace
-Roost
-Earthquake
Say hello to Other Aerodactyl. Archeops can borrow its fellow Rock Flier's stone and use Head Smash off a terrifying 170 Attack, while benefitting from improved defenses to aid its raw power. If the recoil scares you, use Stone Edge. If the accuracy scares you, use Rock Slide. Aerial Ace is secondary STAB and can also seal kills when you really can't afford to miss. It can and should Roost (especially with Head Smash), and Earthquake cleans up anything STAB doesn't hit while also being a reliable attack option.
Anyway, I'm interested to see how broken this thing may or may not be. Let's see how it handles some of the bigger threats in this meta.
252+ Atk Tough Claws Aerodactylite Archeops Head Smash vs. 252 HP / 252+ Def Slowbronite Blissey: 363-427 (50.8 - 59.8%) -- guaranteed 2HKO
Ooh, ouch. That's against a fully defensive variant, too. Meanwhile, Blissey need three Seismic Tosses to toss it away, and Archeops can Roost too. (Yeah, I'm kinda thinking two-attacks Blissey isn't such a good idea, even off 105 SpA.)
252+ Atk Tough Claws Aerodactylite Archeops Head Smash vs. 252 HP / 4+ Def Blue Orb Ferrothorn (Relaxed Nature): 156-185 (44.3 - 52.5%) -- 21.5% chance to 2HKO
Sounds impressive...until...
252 Atk Blue Orb Ferrothorn Iron Head vs. 4 HP / 0 Def Aerodactylite Archeops: 324-384 (110.9 - 131.5%) -- guaranteed OHKO
Welp.
Considering Blue Orb Ferro is likely to be a common sight, I would call Archeops solidly checked. (Don't switch Ferro into it, of course.) But a single check does not an unbroken mon make. Alright, let's see how more traditional threats fare.
252+ Atk Tough Claws Archeops Head Smash vs. 252 HP / 252+ Def Multiscale Lugia: 262-309 (62.9 - 74.2%) -- guaranteed 2HKO after Leftovers recovery
Yikes! Remember that Lugia is supposed to be difficult to get past. Granted, Lugia is at a type disadvantage. When I actually read the type chart and find a neutral target, let's test it against Giratina-A, the other Great Wall of Ubers.
252+ Atk Tough Claws Archeops Head Smash vs. 248 HP / 252+ Def Giratina: 277-327 (55 - 65%) -- guaranteed 2HKO after Leftovers recovery
0 Atk Giratina Dragon Tail vs. 4 HP / 0 Def Archeops: 75-88 (25.6 - 30.1%) -- guaranteed 4HKO
So Tina can live a hit and phase it out, temporarily removing the problem. That's still terrifying power against one of the best defensive Pokemon in the entire game.
252+ Atk Tough Claws Archeops Head Smash vs. 0 HP / 4 Def Arceus: 372-438 (97.6 - 114.9%) -- 87.5% chance to OHKO
252 Atk Life Orb Arceus Extreme Speed vs. 4 HP / 0 Def Archeops: 92-109 (31.5 - 37.3%) -- 82.9% chance to 3HKO
Factoring in Head Smash recoil, E-Killer can be a shaky check, although He needs a clean switch and a LOT of help from the RNG to stand a chance and can still go down in one hit anyway.
252+ Atk Tough Claws Archeops Head Smash vs. 248 HP / 252+ Def Yveltal: 650-768 (142.8 - 168.7%) -- guaranteed OHKO
0 Atk Dark Aura Yveltal Sucker Punch vs. 4 HP / 0 Def Archeops: 168-198 (57.5 - 67.8%) -- guaranteed 2HKO
Yveltal OHKOes with Foul Play, so it can take it down on the switch with good prediction, but if it gets in safely, not much you can do here.
This Archeops is a major threat, as you can see. You can also see how the balance of power is shifting away from the Ubers and toward the Mega-empowered regular mons. Broken? Hard for me to say, since Ferro can check it, but there's a ton this can do once its full power is unleashed.