Hi there 4Skyrim!
No, it is not huge, though it's priced as if it is. Skyrim is hundreds of hours worth of gameplay. Dawnguard costs 1/3 of the original price tag and we do not get 1/3 of its gameplay hours, not even close. Andlet us consder most of the tech, i. e., is already in place and thus the developments costs were severely cut. Still, we are beeing chargedfor 1/3 of the original price tag. There was a moment in hat G4TV interview when Todd's selfconciousness about the steep price was quite evident. He felt the need to state future DLC packs will be cheaper.
To be honest, I'd rather pay Bethesda to continue to update the game with patches, expansions, etc. than have it released and just go dead. These patches that update the game and add new content are free, so that's made up for whenever dlc or expansions are released... I would assume atleast. Either way, I have no issue paying for quality content.