Funnily enough - they do actually take fan submissions for bosses - https://megaman.fandom.com/wiki/Boss_character_contest https://megaman.fandom.com/wiki/Boss_

Funnily enough - they do actually take fan submissions for bosses - https://megaman.fandom.com/wiki/Boss_character_contest https://megaman.fandom.com/wiki/Boss_character_contest - but you’d need to do it during the development time, and probably mail into Capcom JP. Bad luck, there.