Corviknight
Why isn't this set working well? Do you frequently switch it into Heatran or Koko or something, or do you just not choose to switch out against bad matchups? Mirror Armor is not too good since it's a really specific ability which only effectively counters Landorus-T, which Pressure Corviknight already has a great matchup against. Pressure has the benefit of PP stalling Stealth Rock with Defog.
Corviknight @ Leftovers
Ability: Pressure
EVs: 252 HP / 168 Def / 88 SpD
Impish Nature
- Body Press
- Brave Bird
- Defog
- Roost
Landorus-Therian
A STAB Earthquake does as much as a super-effective Brick Break, which means the move's effectiveness is null unless you're facing a screens hyper offense team, which is pretty specific. With 252 Attack EVs, Knock Off has the benefit of OHKOing Dragapult after Stealth Rock (and having a 50% chance to OHKO without them), and removing a defensive switch-in's Heavy-Duty Boots / Leftovers is always useful. Since you don't have a Stealth Rock setter which is mandatory on pretty much every team, you should use defensive Landorus-T.
Landorus-Therian (M) @ Leftovers
Ability: Intimidate
EVs: 252 HP / 164 Def / 92 Spe
Impish Nature
- Stealth Rock
- Earthquake
- U-turn
- Knock Off
Tapu Fini
Modest and max Special Attack on Calm Mind Tapu Fini are never good on a Pokemon that's supposed to soft check things and set up. Ice Beam is also not very useful since its main targets (Rillaboom and Zapdos) can't switch in very well due to Scald, especially Rillaboom, who despises burns. Taunt should be used to prevent any funky shenanigans used by the slower defensive Pokemon you should usually be setting up against. I'd also suggest Draining Kiss over Moonblast since Tapu Fini needs some sort of recovery.
Tapu Fini @ Leftovers
Ability: Misty Surge
EVs: 252 HP / 192 Def / 64 Spe
Bold Nature
- Calm Mind
- Taunt
- Draining Kiss
- Scald
Alternatively, you can use Slowking, since it forms a great defensive core with Landorus-T.
Slowking @ Heavy-Duty Boots
Ability: Regenerator
EVs: 252 HP / 4 Def / 252 SpD
Sassy Nature
IVs: 0 Atk / 0 Spe
- Scald
- Future Sight
- Slack Off
- Teleport
Blaziken --> Heatran
Blaziken is awful without Swords Dance. Focus Sash is not a good item because of how popular entry hazards are, and because Life Orb gives it a necessary power boost. Blaze Kick or Flare Blitz should be used over Fire Punch, and there is no reason to use Brick Break over Close Combat. Since Sash is bad and you're not going to lose your Life Orb anytime soon unless you switch Blaziken into Knock Off (bad idea), you should replace Acrobatics with Thunder Punch. Fire and Fighting is resisted by Slowbro, Slowking, and Toxapex, but Swords Dance boosted Thunder Punch destroys Slowking and does decent damage to Slowbro and Toxapex. Blaziken is a pretty mediocre Pokemon and you're better off using better Fire types like Heatran and Volcarona. Heatran is the better option here since it can trap and remove Pokemon which your team is going to struggle against.
Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 HP / 136 SpD / 120 Spe
Calm Nature
IVs: 0 Atk
- Magma Storm
- Toxic
- Taunt
- Stealth Rock
Zapdos --> Zeraora / Weavile / Garchomp
You already have a Defogger in Corviknight, so Defog Zapdos is out of the picture. Rain Zapdos is used best on full rain teams instead of it being its own rain setter. Also, Aguav Berry is bad compared to Heavy-Duty Boots. Your team lacks a powerful physical attacker (Choice Banded Dragapult and physical Dragapult as a whole are bad), so your choices are mainly Bulk Up Zeraora, Swords Dance Garchomp, Swords Dance Weavile, and Choice Band Weavile.
Garchomp @ Life Orb / Leftovers
Ability: Rough Skin
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Swords Dance
- Earthquake
- Stone Edge / Fire Fang
- Scale Shot
Weavile @ Heavy-Duty Boots
Ability: Pickpocket
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Swords Dance
- Triple Axel / Icicle Crash
- Knock Off
- Ice Shard
Weavile @ Choice Band
Ability: Pickpocket
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Triple Axel
- Knock Off
- Ice Shard
- Low Kick
Zeraora @ Heavy-Duty Boots
Ability: Volt Absorb
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Plasma Fists
- Knock Off
- Close Combat
- Bulk Up
Dragapult
You can keep Dragapult, but as I've said before, physical Dragapult is pretty bad. Phantom Force's extremely annoying 2 turn effect makes Dragapult effectively have only one good physical STAB move in Dragon Darts, which can easily be switched into by the common Fairy and Steel types. Ghost is an incredibly offensive type, and Special Dragapult has all the tools it needs to abuse it, having a great Special movepool, STAB Shadow Ball, and a great speed tier making it the best Choice Specs user in the metagame. Alternatively, you can run a Hex cleaner set to spread paralysis/burns in the early-mid game and then clean up late game.
Dragapult @ Choice Specs
Ability: Infiltrator
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Shadow Ball
- Draco Meteor
- U-turn
- Hydro Pump / Thunderbolt / Flamethrower
Dragapult @ Heavy-Duty Boots
Ability: Infiltrator
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Hex
- Draco Meteor
- U-turn
- Thunder Wave / Will-O-Wisp
