Imho the Fairy type should've just been the justice/good/holy type. It being "le tricksty prankster magical creatures xDD" is pretty redundant and stupid since Dark could've easily fit that niche.

Mons like Mawile and Mimikyu could easily have their Fairy type switched with Dark, while mons like Florges, Gardevoir or Togetic would keep the Fairy/Light/whatever type that would mostly be oriented towards pureness and holiness and all that.