We felt that many of Lucario's Brawl animations looked somewhat lacking in force, with generally slow moving, meditative or mystical motions rather than the satisfying strikes one might expect of a steel fighting type. At the same time that we were trying to make some of his animations looks "snappier" we were also playing with the concept of a magic-system of cancels that might bring in players from traditional fighting games. These two concepts met and as a result some of his attack animations were replaced with motions that payed homage to traditional fighting games, such as Street Fighter. This was admittedly a big stretch in interpreting his lore & style within Smash Bros, and I can understand that someone would get a little bit frustrated with the liberties taken. By now in PM's life, though, there are at least as many players that appreciate the interpretation as those that don't care for it, so we will stay true to preferences of current PM Lucario players on this subjective matter.
As for the Brawl Aura system, though, we had objective reasons for removing it. As others have stated, despite the rather curious popularity of comeback powers in current fighting games (X Factor, Ultras, S4's Rage & Aura) we don't have any desire to incorporate such a feature into our mod. It's unfortunate that the core aspect of Lucario that you're drawn to most is a patently uncompetitive design feature. You can continue to discuss things here, if you wish, but the dev team is pretty firm about not backpeddling on his Aura system. We've chosen a system that rewards Lucario for successfully engaging the opponent rather than rewarding him for getting hit. If you want the latter check out Smash 4.
