Most likely to join:
* Noctis from Final Fantasy 15 because there is Akuma, Gesse Howard, and now Heihachi in Smash.
* Luke fon Fabre from Tales of the Abyss because of the whole 7 motif (there is a whole big deal about #7 for Fighter 7), and recently "The Arrow was Shot" theme from Abyss is going to be added in the upcoming Taiko no Tatsujin's DLC.
* Neptune from Hyperdimension Neptunia because of the recent announcement for the Switch port of Megadimension Neptunia VII.
* KOS-MOS from Xenosaga because of the unlikely event that Monolith Soft directer asks for her inclusion instead of a Xenoblade character(s).
Edit: Also, Itsuki Aoi & Chrom or Tsubasa Oribe & Caeda from Tokyo Mirage Sessions ♯FE.
What I want to see: Atelier, Musashiden, Bravely Default, Chrono Trigger, Etrain Odyssey, Grandia, Story of Seasons, Inazuma Eleven, The Legend of Heroes, Lufia, Neptunia, Ni no Kuni, Phantasy Star, Power Pro-Kun, Radiant Historia, Resonance of Fate, Rune Factory, SaGa, Shining, Shiren the Wanderer, Skies of Arcadia, Souls, Star Ocean, Suikoden, Summon Night, Valkyria Chronicles, Xenogears, Xenosaga, Xenoblade, Yakuza, or Ys.