Mostly the combination of 'blood-sucking' and 'intellectualism undone by said blood-sucking' struck me as reminiscent. Ah well.

While they do have powerful abilities, I'd be more inclined to make use of them if they were RHD 3/LA 1 rather than the other way around, and I don't really think two more monstrous humanoid levels ups their power significantly. And of course it avoids the confusion about 'first RHD is replaced by first class level'.
Although I freely admit I despise level adjustment on principle, which contributes to the above.