I'm happy it's not the latter, as I was worried there for a second. I'll try to explain. The two selling points of the game were basically vampire lord and crossbow. That's why I'm using those two. Doing the vampire side you do get a crossbow, but it's only one, you can't smith it or smith bolts for it. The ones you get later on the dawnguard are much better. Dawnguard gets those plus vampire lord form, granted that they don't get the four pieces of equipment to make it stronger, but thats negligible considering they aren't that great and you only get to wear two I think. I might be one, but I don't know.
...Crossbows are the selling point...
Again, I'm in disagreement with you. I'm sure there are others that might agree with me, that the draw was Vampire Hunters vs Vampires...
Again, materialism. It's a weapon. An object. Insignificant to the grand scheme of things. Dawnguard starts shooting at me with a crossbow, I start throwing my Vampire Lord powers at him and he's dead because he's too busy reloading.
REAL tactical advantage.