If your game requires players to police themselves for balance that does not speak well for the quality of your work.
It's not as simple as that statement makes it out to be, most games will require at least some extent of self-limitations in order to achieve the level of balance one may desire, which might also not be the same for everyone. Game balance is to an extent an objetive matter, but also has a subjective component, and the lines that divide these parts aren't as easily drawn as you might think.
That's one of the first things you're hit with in the original BG games. Do you believe that most players stick to the first roll they get? No, most players will keep rolling until they get something they're satisfied with, and those numbers will change from player to player.
Of these changes the only one that seems worrying is how they'll tweak spell slots when multiclassing, but we have absolutely no information of the severity of the changes and many people here just seem to be assuming the worst.