1. I'm sure this has been stated countless times already, but the fact that Serana can't be married is actually cruel. I wasn't even planning on marrying her (seriously, I play skyrim to get away from the women in my life), but the fact that literally the only character in the game the you develop a relationship (especially one where there are so many damn hints and signs of affection) can't be married is just cruel. WTF MAN!?
2. Has anyone else noticed the bugs involving Serana's follow/wait feature? During the later stages of the quest line, if you tell her to wait you will not get an option to get her to follow you. She can also disappear from the game if you leave the area.
3. Why aren't Dawnguard weapons (aside from the crossbow) also sold by the merchants at the castle? I'm not sure if I've even seen all of them because I've only spotted the warhammer and war axe in a few areas.
4. If you're still a vampire, Isran will still refuse to talk to you even if you have Auriel's bow. This means you actually have to go and cure yourself if you want to advance the quest line.