Hey! This is a pretty cool looking team. I don't have too much to say about it since it looks pretty solid. I think replacing Keldeo with Gengar was a really good choice for your team since it complements your volt-turn core really well. Rotom-Wash lures in pokemon like Clefable as well as grass types for it to Volt Switch into Gengar, and defensive Landorus-Therian takes on the physical attackers such as Talonflame and Scizor that can threaten Gengar with their priority attacks.
Most of the issues I see with the team are with EVs. The one notable change I want to make is to replace Choice Band Tyranitar with Choice Scarf Tyranitar because Mega Medicham, Gengar, and Clefable all threaten stall and defensive cores, so it's not necessary to add another stallbreaker. Plus, the team could use something that's faster than max invested base 110 +Spe (or 350 speed) pokemon, and a scarfer is perfect for that role.
Tyranitar @ Choice Scarf
Ability: Sand Stream
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Stone Edge
- Pursuit
- Superpower
- Crunch
For the EV changes, I suggest changing Rotom-Wash's spread to 248 HP / 216 Def / 44 Spe. The 44 Speed EVs are important for Rotom-Wash on this team because it's the only answer to +6 Azumarill. Having 44 Speed EVs ensures that you outspeed Jolly max speed Azumarill. Next, I suggest changing Landorus-Therian's spread to 248 HP / 244 Def / 8 SpD / 8 Spe with an Impish Nature. Defensive Landorus-Therian shouldn't be running any Attack investment because it needs the defense EVs to be able to stomach hits from strong physical attackers better. The same goes for attack boosting natures. 8 SpD EVs ensures that Landorus-Therian can survive an HP Ice from Mega Manectric from full health and 8 Spe EVs allows it to outspeed max speed base 50 +Spe pokemon as well as 44 Spe EV Rotom-Wash. Finally, I suggest changing Clefable's spread to 252 HP / 172 Def / 84 SpD. Unfortunately, this does make you weaker to Keldeo, which is already an annoyance to your team, but I think it's necessary in order to give the team a more reliable dark resist for pokemon such as Weavile and taking pressure off of Landorus-Therian by allowing Clefable to take on pokemon such as Mega Lopunny because without those defense EVs, Clefable can't take two hits from these pokemon's STAB moves.
I hope this helps the team out a lot more. Good luck on the ladder!
Summary of Changes:
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Change spread
Change spread
Change spread