I love fighting games, any character from a fighting game would be cool to see! (especially Sol Badguy or Ragna the Bloodedge).
Characters from Koei Tecmo would be cool to see, Ryu Hayabusa and Kasumi are the natural choices.
Another indie pick wouldn't be bad, Sunny/Omori from Omori would be interesing, making use of the emotion mechanic.
Of course a first party game could also be in, and I think someone from Metroid would be cool, like Raven Beak. XC3 is also in the way, but I think it would be better to wait to the release of the game.
Visual Novels are represented with Phoenix Wright, but another representation of the genre wouldn't be bad, someone from any Type-Moon work (Saber is the most obvious pick but maybe there is chance of another character like Arcueid Brunestud or even Aoko Aozaki since her game got a rerelease in Switch) or Danganronpa would be nice (maybe a multiple character like Hero, using the MCs of each game has skins).
Elden Ring gives once again more recognition to From Software, not matter if is the Elden Ring avatar (I don't known their name), Sekiro, the Hunter, any of the Dark Souls avatar (most likely the first one, the Chosen Undead) or even Artorias or Solaire are good picks.
FPS are another genre that lacks representation, so either Master Chief, the Doom Slayer or the more underground pick of William J. Blazkowicz would be some of my ideas.
And finally for my super bias pick, Dante, Dante is one of my favs and in general was one of the most solicited characters from Ultimate, so I think he is another good choice (another Hack n' Slash character in general would be cool tbh).
Edit: After thinking it more, some other cool ideas would be Marvelous rep (Travis or either Yumi or Asuka), someone from Ubisoft (an Assassin or Prince of Persia would be my choices, but of course most people would think in Rayman) and a more retro character (Final Fight, Shinobi or Street of Rage would be cool, also could be reps of the Beat em Up genre)