Right, so people who favor evolving during battle would like:
- evolve only by exp level up. No evolution items.
- opponents can't evolve during battle. Only the player's pokemon can.
- evolve when the opponent has fainted, and when the pokemon has leveled up.
Main reason for liking the idea:
- anime-style action. Chance to overcome battles with upgraded power.
- evolve immediately so the pokemon doesn't skip any moves.