I'm not saying it's cheating, but pretty much any fighting game before SF6/Tekken 8 was not built with SOCD (Simultaneous Opposing Cardinal Directions) in mind.
Add to that the fact that execution is a large part of what establishes a skill gap in most fighting games and the myriad execution shortcuts a leverless can do, and it completely trivializes certain powerful techniques that would otherwise be difficult to pull off without many hours of practice.
Korean Backdash comes to mind. SUPER important in mid-high level Tekken and it's very difficult to do, yet someone who's never played a fighting game can be KBD'ing in 3 minutes with a leverless.
That's one of many examples.
Having said all that, I don't think it's cheating and I have one myself (though I still prefer stick).
You boviously know a lot more than me on the subject and raise interesting arguments.
Fro m my neophyte standpoint, it seems half of what the players do with any fighting game are not planned or intended by the devs. That's the beauty of it, finding crazy strategies to be the best.
About the trivialization of difficult techniques, i bet the pro will find other extremely difficult to execute techniques with time, maybe using leverless sticks. Don't underestimate human ingeniosity !
ANyway, this new technology is making waves in the community because it changes every habit people have and force them to rethink their way of playing if they want to win again. Tough times for them but they will come out stronger.
What is the saying again ?
"Tough times bring hard men, hard men bring good times, good times bring smash bros players..."