ORAS Ubers A team built around Mega Mewtwo X. Please rate, critique and scrutinise!

[Scomo]

Mewtwo-Mega-X @ Mewtwonite X
Ability: Unnerve
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Low Kick
- Taunt
- Earthquake
- Ice Punch

Groudon-Primal @ Red Orb
Ability: Desolate Land
EVs: 252 HP / 56 Def / 200 SpD
Relaxed Nature
- Stealth Rock
- Precipice Blades
- Lava Plume
- Dragon Tail

Arceus-Dark @ Dread Plate
Ability: Multitype
EVs: 252 HP / 80 Def / 176 Spe
Timid Nature
- Calm Mind
- Judgment
- Recover
- Refresh

Xerneas @ Power Herb
Ability: Fairy Aura
EVs: 184 HP / 28 Def / 252 SpA / 44 Spe
Modest Nature
- Geomancy
- Moonblast
- Thunder
- Focus Blast

Zekrom @ Choice Scarf
Ability: Teravolt
EVs: 252 Atk / 4 SpA / 252 Spe
Naughty Nature
- Outrage
- Bolt Strike
- Draco Meteor
- Volt Switch

Genesect @ Choice Scarf
Ability: Download
EVs: 248 Atk / 8 SpA / 252 Spe
Naive Nature
- U-turn
- Iron Head
- Ice Beam
- Explosion

I chose Mega Mewtwo X because it has the highest base stats of any Pokémon; I reckoned it would be the most powerful, obvious, and plainly best option. All other Pokémon were selected using the teambuilding advice on the Mewtwo page in the Strategy Pokédex.

All advice and guidance welcome :)

 

[Lord Outrage]

Scomo please describe each Pokemon in 3-4 sentences: moves choices, role of the Pokemon on the team, etc... so I can give you a rate. This will get locked soon too unless you do that :/