Hey as long as you guys aren't paying everyones 15 bucks a month, then what can you do to stop them? Nothing. If they enjoy spending time re learning classes and whatnot every patch then that is on them. Maybe the enjoyment they get out of the game is getting high rating every season or being able to nuke every class.
I do agree that if you play a class in the game and you hate it but still play because it's the best right now, than that is kind of sad and it will get your burnt out of the game faster than normal. do what you want to in game.