Another thought that would be an easy add is that other games like this I played. The text on the characters changes as the relationship progresses so in the character section it could say "Rin is the frienf always challenging him." but after you defeat her "Rin is the love interest drawn to his strength." Stuff like that.
And I always like stats if thats not to wierd like # of Creampies, # of Bjs things like that in the character section for each character. Again just thoughts for fun details.