If you don't mind me asking, why don't you want Dawnguard?
It's really easy to understand.
I mean you start a new game and next thing you know a character you liked gets killed by them hound dogs before you get to her.
Needless to say I was in Windhelm, 1 vampire attacked the city, nobody died.
But then I walk outside across the bridge the person who sells horses died instantly to the hound dogs and now I can't buy any horses there anymore.
I'm only level 13 so you can see the problem, this DLC is really for more seasoned characters who completed loads of quests and bought all the horses already.