Full moon ability to boost psychic and fairy type moves I feel is required. This will be a perfect counter balance to new moon.
Do you mean weather effect? Fairy is already an overpowered type, it doesn’t need a weather effect to add to that imo.
Wouldn’t call it OP. Typing wise, yeah, it has great offensive coverage, but it takes a lot of neutral hits and most of the Pokemon aside from HP Azurill and the legendaries are kinda forgettable (not sure about new Deltas/Megas). Most are special walls or clerics, and there’s not really a decent sweeper to speak of apart from Gardevoir. That said I wouldn’t say a new weather condition is a great solution.
I mean, Mega Mawile is Ubers for a reason. I would call Azumarill a sweeper too. Then there’s Mega Altaria, which can sweep if you go for the Dragon Dance set. Specs Sylveon and Life Orb Clefable both hit incredibly hard as well, even though they’re pretty slow.
Added to that, the only two super-effective types are Steel and Poison, which are primarily defensive typings without a great selection of moves.