Overall I enjoyed it quite a bit. Really the only problem is other players being shitty but there isn't much Blizzard can really do about that. It's like complaining that a dungeon is too hard because an idiot DPS decided to pull the entire first room. That isn't a dungeon design issue that is players being crappy issue. Most of the groups I got actually weren't that bad and most tried to stay within theme. The guild groups and groups tha didn't give a shit did at times ruin the fun but again, I don't really see what Blizzard could do about that issue without any "fix" being abused to make even worse problems.
Best I could say is maybe adding a sort of personal "like" vs "dislike" for each player people are grouped with and preffering "liked" people and avoiding "disliked" people. But a system like that would probably involve more than they are willing to do for a microholiday.