Constructive criticism needed for my rain team OU

Toxicroak @ Black Sludge
Trait: Dry Skin
EVs: 120 Atk / 252 HP / 16 Spd / 120 Def
Adamant Nature
- Swords Dance
- Substitute
- Sucker Punch
- Drain Punch

Using this guy for the crazy healing from dry skin + black sludge in rain along with setting up swords dance behind sub, been unsure between sucker punch and ice punch, using sucker punch at the moment as I have a distinct lack of priority moves

Ferrothorn @ Leftovers
Trait: Iron Barbs
EVs: 252 Def / 252 HP / 4 Atk
Relaxed Nature
- Leech Seed
- Protect
- Stealth Rock
- Power Whip

Love ferrothorn as a wall, using him for covering the weaknesses for the water pokemon mainly along with ice and psychic for dragonite and tentacruel. Got leech seed for general drain / healing and protect when I'm falling behind on health and/or want to see what move my opponent is going to use.

Keldeo @ Choice Scarf
Trait: Justified
EVs: 252 SAtk / 252 Spd / 4 SDef
Modest Nature
- Hydro Pump
- Secret Sword
- Surf
- Hidden Power [Ice]

Using this as a revenge killer with the choice scarf, hydro pump for maximum damage and surf for reliability if its a guaranteed kill, secret sword as the second stab move and HP ice for dragons, pretty happy about this guy.

Dragonite @ Leftovers
Trait: Multiscale
EVs: 252 Spd / 252 SAtk / 4 HP
Modest Nature
- Roost
- Hurricane
- Thunder
- Draco Meteor

Been trying Dragonite out recently, having trouble keeping stealth rock out of the way though so that his multiscale is taken into effect, hurricane and thunder for the accuracy in the rain and roost for getting back to full for multiscale. Also unsure about what EVs to run on this guy as I am pretty new to using him.

Politoed @ Choice Specs
Trait: Drizzle
EVs: 252 SAtk / 252 HP / 4 SDef
Modest Nature
- Hydro Pump
- Psychic
- Ice Beam
- Focus Blast

Using this as my lead generally, using choice specs so that I can take out leads with a hydro pump, psychic seems to take alot of people off guard, leaving fighting types / tentacruel in thinking they are safe. Got ice beam for dragons and focus blast for Steel types.

Tentacruel @ Black Sludge
Trait: Rain Dish
EVs: 240 Def / 244 HP / 24 Spd
Bold Nature
- Scald
- Protect
- Rapid Spin
- Toxic

Using tentacruel as my rapid spin user, actually finding it quite hard sometimes to keep stealth rocks out of the way for dragonite. Got great healing in the rain along with toxic + protect for stalling.

The first one of these that I've done, hopefully got the post right and followed the rules, please help me out with constructive criticism, especially about dragonite because I'm really unsure about him at the moment.

Great team you have here. There are a couple of changes I would like to make. First off, toxicroak does not need both Dry Skin and Black Sludge. Toxicroak would greatly improve by running life orb. You heal back the damage from life orb anyway. Also over substitute I would run ice punch. Toxicroak does not have much time to set up substitute. Though status may be a problem, ice punch is coverage that is greatly needed. Another thing that would greatly benefit you is to use icy wind over HP ice and HP bug/electric over surf/hydro pump. Having both surf and hydro pump is redundant and bug is for hitting grass and psychics like celebi and electric is for hitting jellicent. Another thing is that keldeo could run life orb because max speed keldeo only loses to very few things. This is optional as personally I like the power better on keldeo. The last thing that I would like to say is that it would be much better to run HP Grass on politoed for coverage just because psychic hits only 2 types super effectively, fighting and psychic and HP Grass hits more threats.

Thank you very much for the advice, will give these ideas a try