Sacred 1 had loads of good ideas and hardly any of them worked. With Sacred 2 they tried to fix that and create a game that had options that were meaningfull and weren't just there to give the impression of choice and a chance for players to waste skill points.
I can't remember the level of my Vampiress... hundretsomething I think. The theoretically big thing of changing shape based on daytime was made mood though, since she had such a high life drain on each hit, that she could stay in her vampire form, even during the day without any side-effect, as long as there were enemies to fight. Probably the only character to whom not fighting was potentially the deadliest thing in the game.
Sacred 2 was far from a Diablo clone. No more than Sacred 1 anyway. What it was, was an attempt to take the ideas of the original Sacred and remould them into something that works.