No, there are sections of the game (such as leveling Raven enough to unlock the first dungeon) that require Raven to have sex to progress
you have to get creampied while wearing the cumslut or cumdumpster shirt or whatever
It's just really rare for her to spawn (she also only spawns in the hallway if that helps)
yea and not all of them would make total sense in all the areas, golden girls would be nice tho