I plan to get this now that its on sale, but I'm not actually going to do the MQ right away. I do want to use the change face feature asap though. Is there any way to disable this thing after I change my face (other than deleting it as I don't want to do that.) The main reason I want it disabled is because I've heard stories of vampires killing named npc's in towns I visit etc. I know I can just not go to any towns until I finish the MQ but who knows when that will be.I'm on xbox and about lvl 40. Are the attacks really that bad or am I just worring too much? thx.

Just don't fast travel to towns and you won't trigger the attacks as often. If you do need to fast travel, go to a location close to he town you want to visit and then walk from there.

That being said, I have only lost one towns person in all my vampire attacks - the guards, myself, and various townspeople usually make short work of them.

The attacks aren't that bad. The people screaming OMG GAMEBREAKING! were just doing the standard internet blow-stuff-out-of-proportion-routine.
Every attack in my two playthroughs with dawnguard were easily stopped even with my non optimized character (I don't use smithing & enchanting, meaning that if you do, you'll steamrole over these encounters).
The only casualty in my game was a guard.

If you want to avoid it completely, I suppose you could stay indoors or avoid cities at night. Also I believe that if you don't use fast travel, the attacks only happen rarely.

thx guys, so they aren't so bad