Humble, you must realize that each mod has a different aim, a different goal and purpose. Brawl+ was made because they wanted to change the 'feel' that was vBrawl, not preserve it. They wanted it to be what Brawl should have been, without drastically changing the basic concepts that comprise vBrawl. This means they often didn't want to change animations because, and entire moves, because it would no longer resemble the core game it was aiming to better: vBrawl. In a nutshell, Brawl+ added as much as it possibly could before losing the vBrawl way of things. They wanted the game to be inviting to all of those who already play and like vBrawl. To these players specifically, heyd be mad that characters were changed aside from the addition of many tournament based things.
BBrawl took another approach. Their approach was let's make as few changes as possible, presserving as much as vBrawl as possible, but make a better game. Brawl-, from what I understand, is designed to make each character ridiculoussly good. As said in their OP, "if everyones super, no one is-- but it sure is fun!" They can do whatever they want in this project, there not trying to keep it entirely similar to vBrawl. Heck, DK has an item.. haha.
P:M on the other hand doesn't care about vBrawl. Their goal is to make Melee 2.0. Which I am very excited for. They are working to bring many characters to match their melee equiv. Obviously they don't intend on making a character suck just because they did in Melee. They're trying to take the best qualities of said character from Melee. As for the characters who weren't in Melee, they can be creative... They can do whatever they want to make the character more technically rewarding. New ATs anyone?
Good stuff. :D