Mistwell
Crusty Old Meatwad
Its out of whack with those assumptions though. Look at class functions like the hunter bonus damage, +2 damage off the duelist fighting style, the clerics bonus dice of damage at level 8. Even spells as class features hunters quarry and hex.
You've played probably more games than anyone I've ever met, and possibly more than anyone else on this message board. So you tell me - have you found that Great Weapon Master, "simply can't be allowed to remain?" Have you found that it, "destroys the fundamental assumptions of the game," in a way that is so meaningful that you've had to change the rules to accommodate it?
Because I think there is an argument of degree here. I think it's fair to say this feat is on the high end of the scale of power in the game, without going so far as to say it breaks the game down and simply cannot be allowed. I think that's a pretty important distinction.