I have a basic understanding of his jank
Not convinced. Your opening post on the topic came off as less generally educated on Lucario's mechanics than I was within my first week of playing PM. As such, a lot of what you're saying strikes me as willful ignorance rather than a design problem with the character.
Lucario's kit is quite clearly tuned around the OHC mechanic. He generally doesn't follow up very well without making use of it. Even with the magic series, his combo potential is not as good as you seem to think. Good use of his supers is what really makes his punish game so explosive because it can either extend combos in unusual ways or net him early kills. Everything else is basically a sped-up version of what other characters do. Not all of his stuff is true combos, he still makes use of frame traps and tech chases. His kit is also relatively devoid of DI mixups - it's not like every hit is his own personal variant of Sheik's old throw mixups. Even if you don't fully understand what's going on, you should have a general sense of how to respond once you get over the initial surprise of seeing his OHCs.
Given that knowledge, counterplay becomes pretty clear. The primary goal is to limit his ability to generate and utilize aura. The less he gets off each conversion and the more often he's forced to use it for things other than damage, the more he'll struggle. This is a principle that is both effective and relatively simple to apply.
I honestly don't see the problem here. Yes, it's unusual for a Smash game. No, it's not nearly as opaque to the opposing player as you're trying to make it out to be, and the PMDT has done a good job of cleaning up his design with changes like ASC endlag (still useful, but no longer overshadows the rest of his magic series in so many situations) and changes to aura generation.
I'd argue Fox is not very interactive if played optimally since he just stays across the stage shooting lasers at you until "you" do something and you have to approach Fox or the lasers will rack up % on you.
I really don't like Fox's lasers. They're incredibly rewarding even in their nerfed state, yet have very one-dimensional "counterplay". Not fun. I'd much rather play with or against something like Wolf's blaster, that thing is cool. Too bad I hate Wolf's shine sound effect, RIP
Speaking of sound effects, Mewtwo's fair? Biggest nerf was the audio change. Sounds like a knife through wet sandpaper, do not like.
Reminder that Lucas is really good. Somebody not named PF/Neon needs to break out and show what's really up with this character. So much he can do, so many solutions to perceived issues in his kit if you're looking at him from that state of mind.
edit before I forget:
Are you sure you read what I proposed correctly?
I skimmed and missed the specific suggestion, my b. That sounds like a pretty awkward workaround, assuming it's something that'd even be reasonable to implement. Can't say I much care for it.
