So many bigs, so many missing quest dialouges, so many glitched character models or unessessesary essential tags (Isran remains essential if you sided with the vampies and wanted to wipe out fort dawnguard; everyone else could be killed, just not him...he needs to die if you sided with Harkon, as it makes sense, roleplay wise.)
I do hope bethesda can patch this DLC; I don't see why they can't, it's easy, make it so if you have Dawnguard installed, once the game is loaded, it loads the DLC too, right? well, it would then check to see if the downloade addons have any recent alterations, if one or more does have a updated version, it will then install the patch and not intefere with any 'vanillia' Skyrim or it's own independant patches.