I DLed this the other day since I wanted more Skyrim stuff. I tried using one of my two characters that have completed the main quest. Here is my take on some of the dialogue of Dawnguard with a minor spoiler warning
Chick in box- Wow how long have I been sleeping?
Me- A long time, say is that an elder scroll on your back?
Chick in box- Yes it is a very rare and powerful artifact which few may ever possess.
Me- Well what do you know I have one too, what a coincidence!
Chick in box- WTF!! does everyone in this era have an Elder Scroll!??!
Me- Wellll, not everyone...
Then we meet head vamp...
Head Vamp- "I can give you the power of a Vampire Lord blah blah blah..."
Me- "Well gee, I don't know you see, I am already a werewolf and can summon dead heroes of Sovengard, and also have this pet dragon that comes on command."
Head Vamp- "Get out!"
Other than that I find using a character that has done the main quest is kind of boring(aside from nobody seeming to know who you are). I tried a higher difficulty but that was not much better. So now I am trying to play dead is dead on regular difficulty, so far got killed at level 7 by going somewhere I should not have. Still much more interesting if you play for keeps.
One day the West will fall. But if the Liberty for which we fight is taken up by the world then the West will not have failed.