I just feel like Lucario's Aurua has no discernible drawbacks to it. It is, in a nutshell, a mechanic that makes him stronger the more he's getting his ass handed to him.
You can argue that he's incredibly weak by default or that his true strength only manifests when he's in danger, but...why? Is he that dependent on what is essentially a weird gimmick? Why can't he at least be balanced more professionally - make him a bit stronger by default and allow him to gain a moderate boost to his stats when in danger? Why does he have to go from "absolutely piss weak" to "unstoppable killing machine" the better you are at killing him? You should be rewarded for doing well, not trembling in fear because you've activated his metaphorical trap card; hell, I'd even be willing to accept it if it just had some sort of weakness to it, like he gains more startup or endlag on all of his moves, or if his only notable weakness is the fact that he's close to death, a condition that is the result of you playing the game correctly.
Maybe I'm being a tad too harsh on it, though. After all, rage is a thing and I tolerate it. What really irks me about Aura is the fact that it is, really and truly, way overpowered. The dichotomy between default Lucario and Aura Lucario is just astounding. Why on earth did anybody think it a good idea to have Lucario's true abilities be so overwhelmingly, catastrophically overwrought as to eliminate the need for actual consideration of skill? I get that it's to accentuate the difference between the two forms, but honestly, it just feels hamfisted and poorly thought-out, especially when he could just as easily be "okay character" -> "better character" without the need for such an ungodly transition of manifest power.
Pit doesn't get super-fast arrows and infinite jumps when he's in the red zone; Palutena doesn't get to use her custom specials when she's on the verge of annihilation. Aura is the ur-example of a mechanic that's interesting in theory and dreadful in execution: the opponent is punished for playing well while the player gets to reap the rewards of their own misfortune and turn the tables without any real need for skill or clarity, just take advantage of the overwhelming intensity of the Aura, and go ham as they deem necessary.
/rant
Truth be told, I'm not even sure how much of this I actually believe in and how much I'm saying out of pent-up salt / sympathy for Raziek, but it's said now, and I'm content to move onto something else instead. Feels good to say all the same, and I'm glad to finally get that off my chest~ :3