I'm just going to throw out that I'm back fro ma local and noticed something. A lot of players are *really* coming around to Wuhu Island; I played several games on it (having it counterpicked against me!), and people seem to have grown really fond of it. The stage truly does nothing objectionable; I think some people are a bit intimidated by learning a new travel stage, but if you just have it legal a lot and just hold it out there, I think it's nearly inevitable almost every scene would come around to it.
I hope we see more traveling stages in future smash games because they always seem like the kind of stages that are more likely to be legal. These stages are very dynamic but at the same time are not disruptive enough to feel like your environment is trying to butt in on the match.
To me I feel like the universal stages we have now are ok:
Smashville
BF
FD/omega
T&C
Lylat
Castle Siege
Delfino Plaza
Duck Hunt
Halberd
But I think having two more stages makes the list feel more complete.
Skyloft, Wuhu, KJ64, and Ps2, I think are the best stages to push for.
Wuhu is honestly the best of these likely stages to make the standard due to how little "jank" there is in the first place, the boat is the only polarizing part of the stage honestly.
Skyloft only issue is when a when a part of the scenery can hit you on the traveling platform, but that is it. It would be less of an issue if we knew when and where it happens.
With KJ64, if the issue of barrel camping can be solved then it is legal.
PS2 is honestly banned because it is "janky". Good luck convincing someone that even thought a stage is annoying to play on does not mean it can be legal.