SM OU Can someone please rate my team??

[RekaderEX]

I havent played pokemon in a while and im having trouble knowing the pokemon to make this team truly solid, any help is appreciated!
Landorus-Therian @ Leftovers
Ability: Intimidate
EVs: 252 HP / 112 Def / 144 Spe
Impish Nature
- Stealth Rock
- Earthquake
- Hidden Power [Ice]
- U-turn

Charizard @ Charizardite X
Ability: Blaze
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Dragon Dance
- Flare Blitz
- Dragon Claw
- Roost

Skarmory @ Leftovers
Ability: Sturdy
EVs: 248 HP / 252 Def / 8 SpD
Bold Nature
IVs: 0 Atk
- Roost
- Whirlwind
- Spikes
- Defog

Chansey @ Eviolite
Ability: Healer
EVs: 252 Def / 252 SpD
Bold Nature
- Heal Bell
- Soft-Boiled
- Toxic
- Seismic Toss

Tapu Koko @ Shuca Berry
Ability: Electric Surge
EVs: 32 HP / 88 Def / 172 SpA / 216 Spe
Timid Nature
IVs: 0 Atk
- Thunderbolt
- Volt Switch
- Hidden Power [Ice]
- Dazzling Gleam

Greninja @ Choice Specs
Ability: Protean
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Ice Beam
- Extrasensory
- Dark Pulse
- Hydro Pump

 

[Gross Sweep]

Welcome to Smogon! I'm locking your RMT for the time being as the forum rules require that you provide in-depth descriptions that are at least 3-4 lines for each Pokemon to explain their roles. Please read the rules carefully and take a look at Team Showcase to see the level of detail we require. PM me with updated descriptions and I'll be happy to unlock this.