How so? Certain Up-Bs are improved, but so is every other move for many a character.
Pit, ROB, Jiggles and Sonic (though technically not) are the only characters without damaging Up-Bs in P:M... I think. Them and Lucario are the characters without in Brawl. Ya might as well count Pikachu too since Quick Attack does, what... 2% or somethin', no knock back?