OK. Quick question. What is your opinion on changing Astarte from PoR with Eqyptian god Monsters (Osiris, Obelisk and Ra) from Yu-Gi-Oh?
Completely unnecessary, but they've came up with worse ideas.
Astarte isn't the best boss creature they've ever came up with, but there's nothing horrible about her either.
if the people working on Castlevania decided to put a YugiOh monster in the game as a boss, I wouldn't care much about that either one way or another.
However if you're going to talk about replacing a boss with something, there are far better places to find monsters than Yugioh. I'm still dyinng for a pumpkin tossing headless horseman boss myself.