Man, these new changes will surely have a massive impact on the metagame, and I am not convinced it is in a positive way. I am expecting the new metagame to be much more offensively based than before, more centralized around Huge Power Mega-Mewtwo-X and Mold Breaker Mega-Gengar (and other Mold Breakers) than it already was, seeing as defensive checks have to chose wether to be physical or special, giving offensive mons even more firepower. Offensive checks are more relevant than defensive counters. After taking a look at the damage calc here are a couple of things I notice so far:
-Mega-Gengar now 2HKO'es Yveltal, the closest thing to a counter, with a shell smash boosted Ghost Judgment or Secret Sword
-However, jolly Gale Wings Yveltal can now OHKO Mega Mewtwo-x and Mega-Gengar after Shell Smash with Brave Bird, without a boosting item.
-Slaking can now OHKO Imposter Blissey with a +6 Extremespeed.
-Xerneas can no longer live a +2 Ghost Judgment from moldgar if it's not specially defensive.
-Huge Power Mega-Mewtwo-X no longer needs life orb to OHKO Mega-Gengar with Shadow Sneak
I'm not entirely sure how team preview will affect the metagame, but common pokemon with unexpected ability choices may become more effective, like Wonder Guard Mega-Mewtwo-X and random no guards. Having more than one of a certain poke won't be as effective anymore, as the opponent gets that information from the start.
Anyway, here's a pretty cool set I've been using for a while, it's actually better with the new changes:
Aerodactyl-Mega @ Choice Band
Ability: Mold Breaker
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Brave Bird
- Diamond Storm
- U-turn
- Trick/Close Combat
It seems bad on paper, but it is incredibly effective and 2HKOes the entire meta. Designed to outspeed and kill Mega Mewtwo-x while forcing a kill almost everytime it comes in. It's dual stab alone is pretty much enough, the rest are filler moves; Close Combat allows it to deal with physically defensive arceus and dialga.
With the new EV system it takes advantage on defensive walls being weaker, and is disguised as a perish trapper in team preview.
Calcs for reference:
252+ Atk Choice Band Mega Aerodactyl Brave Bird vs. 252 HP / 252+ Def Swampert: 255-301 (63.1 - 74.5%) -- guaranteed 2HKO after Leftovers
252+ Atk Choice Band Mega Aerodactyl Brave Bird vs. 252 HP / 252+ Def Xerneas: 247-292 (54.1 - 64%) -- guaranteed 2HKO
252+ Atk Choice Band Mega Aerodactyl Close Combat vs. 252 HP / 0 Def Mega Aggron: 212-250 (61.6 - 72.6%) -- guaranteed 2HKO
252+ Atk Choice Band Mega Aerodactyl Brave Bird vs. 252 HP / 252+ Def Groudon: 189-223 (46.7 - 55.1%) -- 69.5% chance to 2HKO
252+ Atk Choice Band Mega Aerodactyl Brave Bird vs. 252 HP / 252+ Def Giratina: 212-250 (42 - 49.6%) -- 87.5% chance to 2HKO after Stealth Rock