Being able to change the damage dealt by a spell is a feature that already exists. Trying to come up with the numbers everyone is satisfied with is the impossible part of what you're suggesting. The custom part, where you can research all you want and tweak it as hard as you like and you wouldn't satisfy people ever. In addition to that, some significant (or, at least, extremely loud) portion of the playerbase is greatly upset by just... random change. Any random change. Or any change they deem random, even if it does not affect their own class. So the happy people you'd gain by, idk, removing warriors from the game would be offset by the people upset at warriors being nerfed, the people upset by the possibility of removing a class from the game, and the people who are flaming the other people who are rightfully upset at their fun taking a hit cuz "suck it up you f*** warrior main, your class deserved it, now stop crying".
You always have to consider all sides. I know that, as a player, it's really easy to dismiss what the opposition thinks, just because your opinion has more merit, because you've played this game for longer, or have achieved higher rating, or did it with a "worse" class - we encounter this almost daily. You are loud, I get that. So is everyone else. It is just not possible to satisfy everyone, and even by trying you'd upset people. My stance is still that helping anyone who ever comes up with stuff that is possibly not blizzlike is the most productive approach one can take.