Well, I'm giving it 10 because it's still pulp adventure fun. But, to be honest, the vampire thing just didn't play with the overall methos of the film.
Although, it was nice to have the Librarian seem bumbling and not as physically capable as the woman he was paired with again. That brains/brawn reversal was extremely fun in the first film and unfortunately dialed back a little in the second. The dynamic worked, and it returns a bit with The Curse of the Judas Chalis.
However... Vampires. Vampires just seem a little too out of place for what the first two films were playing with and it never really worked.
But, the scenery was beautiful the story was still fun and that is all that counts.