My OU tier team, rate/give suggestions

Ok so I'm trying to make an OU tier team and I personally like what i came up with, but seeing as I only recently got back into pokemon and this is only the second team I've come up with, I need opinions on whether or not its good.

Skarmory- Impish/Sturdy/Rocky Helmet
Roost
Brave Bird
Stealth Rock
Defog/whirlwind

Mega Diancie- Timid/Clear Body/Diancite
Moonblast
Diamond Storm
Rock Polish
Calm Mind

Gengar- Timid/Levitate/Life Orb
Focus Blast
Shadow Ball
Sludge Wave
Taunt

Bisharp- Adamant/Defiant/Assault Vest
Pursuit
Sucker Punch
Knock Off
Iron Head

Rotom Wash- Bold/Levitate/Leftovers
Hydro Pump
Volt Switch
Will-O-Wisp
Pain Split

Dragonite- Adamant/Multiscale/Lum Berry
Fire Punch
Extreme Speed
Outrage
Dragon Dance

That's my team so far. I originally had Gliscor instead of Skarmory, with Taunt/Stealth Rock/Stone Edge/Earthquake. I switched them cause I kind of want the defog from skarmory, since my team is so heavy with offense. Well, let me know what yall think and any way I can make this team better. Thanks :)

I don't think Mega Diancie needs both Calm Mind and Rock Polish. Earth Power or Hidden Power (Fire) are important options on it so it doesn't get boned by Steels. That, and Mega Diancie can be threatening by itself even without any boosting moves:
-Diamond Storm
-Moonblast
-Earth Power/Hidden Power (Fire)
-Protect/Hidden Power (Fire)
Nature: Naive
EVs: 32 Atk/224 SAtk/252 Spe
Item: Diancite

or
-Rock Polish
-Diamond Storm
-Moonblast
-Earth Power/Hidden Power (Fire)
Nature: Rash
EVs: 36 HP/32 Atk/252 SAtk/188 Spe
Item: Diancite

or
-Calm Mind
-Moonblast
-Earth Power
-Hidden Power (Fire)/Psyshock
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Diancite

What are the EVs for each of your Pokemon? That's another important component in competitive battling