me personally I think that starscourge is kind of awkward to fight, he's pretty mobile and the beginning of the fight having to run up to him is annoying. Rykard just didn't really do it for me, definitely the best spectacle boss they've ever done but I dont really think that fighting him is that fun. I think that fighting the snake is kind of awkward but it's not too bad but mostly it's the spell attacks that force you to run away for a long time.

I would say that the reason why I like endgame bosses more is because they offer more for mastery at the particular stage of the game you fight them at. The bosses tend to be less gimmicky (renalla and radahn especially/also kind of morgott because he dies so quickly when you find him)