Which notable Japanese developers (that tend to work with Nintendo) are still lacking representation in Smash? The only ones I can think of are Taito (owned by Square), Marvelous, Level-5, NIS, Falcom, Arc System Works, Spike Chunsoft, and Technos (owned by ASW). I guess you could throw in Grasshopper Manufacture as well.
There's also Koei-Tecmo and Hudson (owned by Konami), represented by one AT each, but no playable characters.
For each of these companies, possible characters would be...
Taito: Bub & Bob from Bubble Bobble most likely
Marvelous: The protagonist of Story of Seasons or Rune Factory, or a Daemon X Machina character if they wanted to be promotional
Level-5: Jibanyan from Yo-Kai Watch for the most relevant pick, Professor Layton for the most fan-requested
NIS: Laharl or a Prinny from Disgaea
Falcom: Adol from Ys, no doubt
Arc System Works: Sol or Ky from Guilty Gear, though I have trouble imagining it
Spike Chunsoft: Monokuma from Danganrompa, or maybe Shiren the Wanderer from Mystery Dungeon
Technos: Kunio/Riki from Kunio-kun/River City, or possibly Misako/Kyoko from River City Girls
Grasshopper Manufacture: Travis from No More Heroes, obviously
Koei-Tecmo: Hayabusa from Ninja Gaiden, possibly Akane from Dead or Alive or someone from Dynasty Warriors
Hudson: Bomberman is an AT already, but they could get Bonk or Master Higgins from Adventure Island
Which of these companies would you like to participate in Smash?