Same. And I forget if I pointed it out here earlier, but I think Smash just wouldn't work very well in a 3D environment. Smash has become reputable for being a mixture of the platformer and fighter genres (enough so that it pretty much codified several other attempts at such a hybrid), which makes sense considering that Nintendo's flagship franchise (as well as the obvious namesake to Smash Bros.) is primarily a platformer series. That said, I don't see Smash getting rid of the platforms lest it remove a major part of its identity. However, platforms are tricky enough to work with in a 3D environment even when making a single-player adventure game, let alone a competitive fighting game. Off the top of my head, the only game to even attempt such a thing was ARMS, and putting aside that game's rather lukewarm reception, it has something major which helped it kinda work: ranged attacks and grabs, something which not every character in Smash Bros. would have access to (though I guess to be fair, not every Nintendo character was capable of doing a double-jump along with some sort of semi-flying recovery move prior to the N64 game, either..... even then, it's not hard to see it being an expansion on the almost universal concept of jumping).
Eh, I dunno. I mean, I do get what you're saying about the gameplay being good, but I also think the crossover aspect, the ability to interact with and use these legendary characters in all kinds of situations, shouldn't be downplayed either. As somebody who friggin' loved Subspace (as well as Melee's Adventure before it), it just really annoys me when I see people saying that "core gameplay" is the only thing that matters in Smash, and that all the side modes of the past, not the least of which being a side-scrolling Adventure Mode, apparently deserved to be completely chucked out for Ultimate (a sentiment I've seen quite a bit of).