I agree with Survivian that the casual crowd has a big impact on this, especially since brawl minus is viewed by most people as less competitive.
I think of changing the footstool to taunt, at least to me, is kinda changing a small part of the game. I have to change my muscle memory of how I go for footstools. Instead of just pressing jump, a button close to where your right hand is, you have to move your left hand down or give up a button and still change your reaction.
Some may say just to adapt, but my counter-argument is why didn't nintendo just force competitive players to use the pro controller? it is similar to the gamecube controller.
For casuals, it mostly remove footstools from the game and for more serious players, it forces a change in muscle memory.