I like this one a lot - and actually, I think an otome game (or any other game) with a hard-mode villain story would be super interesting. Some games you get to replay from a different perspective (SoTN Richter mode) but usually it's another protagonist, not the antagonist! There are some games that are from the antagonist PoV (humorously, the Dungeon Keeper games spring to mind) but I dunno if I can name one with both protagonist and antagonist in the same game. Um... Chrono Cross where you were Lynx for a while, I guess?