I like pretty much all of the cosmetic stuff here, like giving his black and white alt back, better taunts and poses, and extra songs and spirits. Some of the moves are good, like swapping the chomp for a shaky grab, giving him some more visceral...
Found on the Super Smash Bros Ultimate subreddit. with a mix of Wario Land and WarioWare moves, a Wario Land stage, a mix of songs from both series and more characters from each:
I'd personally be okay with it.
I think this mechanic moreso depends on the type of game the developers want to design. 1 and VB have their systems mostly due to not having a different direction than "slightly different Mario" yet, but in II and 3 the invincibility feels very...