>>22925958All of the field-changing moves deserve pokemon that automatically start them when they're sent out, if they work like weather generation abilities now and only last 5 turns.
Trick Room and Gravity and those kinds of moves are really cool in concept, but because you waste one turn setting them up (plus another if you want to switch to another pokemon that can really benefit from it outside of the user), you really can't get much use for all of the turns of set up involved.
Porygon2 can really wreck with Gravity + Zap Cannon that hits at least somewhat reliably, but there's just no point in that moveset when it peters out so quickly because of the mechanics involved.