ORAS OU Hi! Could you help with my team?

[Seth_]

Hi!
It is my first post here. I have team like that:
Ferrothorn (M) @ Rocky Helmet
Ability: Iron Barbs
EVs: 248 HP / 8 Atk / 252 Def
Relaxed Nature
IVs: 0 Spe
- Stealth Rock
- Leech Seed
- Gyro Ball
- Thunder Wave

Gengar (M) @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Shadow Ball
- Sludge Wave
- Destiny Bond
- Focus Blast

Azumarill (M) @ Sitrus Berry
Ability: Huge Power
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Play Rough
- Belly Drum
- Knock Off
- Aqua Jet

Bisharp (M) @ Life Orb
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Sucker Punch
- Knock Off
- Iron Head

Diancie @ Diancite
Ability: Clear Body
EVs: 32 Atk / 224 SpA / 252 Spe
Naive Nature
- Moonblast
- Diamond Storm
- Earth Power
- Protect

Darmanitan @ Choice Scarf
Ability: Sheer Force
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Flare Blitz
- Brick Break
- U-turn
- Zen Headbutt

My rating right now is around 1400 and I have hard time getting higher, to the 1500+