This looks like it only needs some simple fixes.
Mega Slowbro
Mega Bro isn't the best in Doubles format, but he should do alright. If you need a pre-Mega ability, go with Regenerator. This lets Mega Slowbro function as vanilla Slowbro, and then Mega Evolve when he needs to. IF you don't go Mega right away, you can play mind games with your opponent. EVs and moveset look good.
Bisharp
For his ability, use Defiant. This lets you get the one-up on all of the Intimidate users (Mawile, Landorus, Gyarados, etc.). Nothing else really needs changing.
Aegislash
For Aegislash, I personally prefer Wide Gurad + Weakness Policy over Substitute + Leftovers, but SubSlash is perfectly viable. Nothing to change here.
Blaziken
This needs a bit of work. Blaziken is nowhere near as good in Doubles than in Singles, since he gets wiped by Earthquake and the omnipresent bulky Waters. I would suggest a change. A Fighting Mega, perhaps? I would suggest either Mega Lucario or Mega Gallade.
Lucario@ Lucarionite
Ability: Steadfast / Adaptability
EVs: 252 Atk / 252 Spe / 4 Def
Jolly Nature
- Close Combat
- Bullet Punch
- Protect
- Ice Punch/Helping Hand
Steadfast lets you get to +1 Speed when you take a Fake Out. Adaptability Close Combat and Bullet Punch are STAB, Protect is a must and either Ice Punch to nail Mega Mence and Landorus or Helping Hand to offer a bit of support.
Gallade@ Galladite
Ability: Steadfast / Inner Focus
EVs: 252 Atk / 252 Spe / 4 HP
Jolly Nature
- Close Combat
- Zen Headbutt
- Protect
- Wide Guard/Drain Punch
Close Combat is Fighting STAB to OHKO Mega Khan, while Zen Headbutt offers a nifty flinch chance as well as Psychic STAB. Protect speaks for itself, and either Wide Guard to block Heat Wave, Rock Slide, Earthquake, etc., or Drain Punch for a bit of recovery.
Amoongus
Use Regenerator for your ability, allowing Amoongus to stay alive longer. EVs and moveset look good.
Rotom-W
I would change his spread to a more bulky build of 252 HP / 232 Def / 24 SpA and a Bold nature. IF you want a purely offensive Rotom, then fine.
That about does it for the rating. Like Guillotine said, EVs are more complex in VGC than Singles. 252/252/4 spreads are fine (Sejun Park used them to win Worlds), but most of the time you will want to EV them to survive certain attacks, so you may end up with something like 172 Atk/252 Spe/84 Def (my Tyranitar's build). For more on that, look at these handy Nugget Bridge articles on custom EV spreads:
Article 1
Article 2
