Likewise, Astarion's mannerisms remind me of Frank'N'Further from the Rocky Horror show, which prevents me from taking him the least bit seriously. This is mostly a voice acting issue, not so much a writing one, but I still hope the writers will tone down those personalities a bit.
I quite like him! He reminds me of the male elves from Oblivion, who drove a lot of players nuts because the dunmer in particular weren't the suspicious, gravel-voiced hard-arses from Morrowind but quite the opposite.
Oh, I don't mean that as a vampire he should somehow sound "more evil", just that his way of talking strikes me as not quite natural, for lack of a better term. It's hard to put a finger on it, it just doesn't click for me. On the other hand, it's early days yet and he wouldn't be the first characer to grow on me once I get to know him better, so we'll see.