I agree Geno is not that likely, but you seem to forget he is still popular. I do expect Waluigi and others to get in before him, but Ido think even if he is a magical gunner, that is no bad thing. Plus, he came from a game where times hits were a thing, and that could be incorporated in his moveset. Not that I think Geno is that likely, but I don’t think you are giving him that much credit. There is that SMRPG remake after all. That should boost his chances some. Besides, I would worry about his competition with Square Enix characters more than Mario characters since he is owned by Square Enix characters. Plus, it is said that Sakurai did want Geno in as a playable in a past Smash Bros. game.
Geno’s popularity I think is partially an exponent of survivor’s bias: At the end of Smash Ultimate’s lifespan he was probably one of the most requested characters, but that’s partially because his Mii Costume returning didn’t put him out of his misery until Sepiroth. Geno had the advantage of a fanbase eager to speculate and the momentum that entailed. Compared to other high-popularity characters like Skull Kid, Ashley, Krystal and Isaac, whose discussion and speculation was shut down in the early days of Ultimate speculation, Geno’s suspicious absence allowed his speculation to snowball in a field where similar characters got thrown in the Assist Trophy abyss. Still, Geno’s factors have never been logical, and all he really needs are Sakurai willing to play ball (he is, on the record, multiple times). Anything else is just extra.
The fact that Waluigi was one of those
and still revived himself in the discussion is the true testament to his popularity, although part of his popularity was
because he was so memetically shot down at first sight. In a field where it wasn’t realistic or feasible to discuss the chances of Ashley, Skull Kid, Isaac and others, Geno soared comparatively, but once the field is truly wide open again and everyone is on the table, Geno might not be the frontrunner so clearly.
Waluigi’s moveset isn’t too hard to construct thanks to his gangly frame and exaggerated animations in the Mario series: Even the most basic move archetypes (Your flip kick Up Air, a bicycle kick Up Smash, a leg sweep Down Tilt) would already be unique for Waluigi because the man just looks like
that, which mechanically already works for a disjointed-spacing playstyle. Some ”crude” animations (A Down Smash kick that buries opponents, a showy spike on Down Air) and potentially some off-kilter hitboxes like WFT and Waluigi can set himself apart from others even without potential Specials. That’s not even talking his mobility stats too, which could be an extrapolation of Luigi’s, with ridiculous vertical jumps and just no traction. Just look at his Assist Trophy: Yes, his weapon is a tennis racket, but he’s
volatile and
cartoonishly aggressive and completely unafraid to kick someone while they’re down.
These Specials can probably be your average Sports/Party/Kart equipment, sure, but starting Waluigi moveset discussion with “He can represent the sports series” or “He should be
the spinoff character” is a flawed frame because, aside from “Mario Party = Random BS Go”, these starting points don’t translate to much gameplay-wise and are merely visual.
is always 1, 
