Not really something "AMAGAWD AMAZING!" but I figured I'd post this so some can get use of it.
When you go to fight Molag'Bal in the quests, and I mean the actual final quest before Veteran Content after you use the Amulet and become pretty much a god, you'll have a ton of small monsters to fight along the way that you can pretty much two hit. Build up your Werewolf ultimate before going in the quest, use it and just proceed to wrecking ball through about 10-30 monsters in no time when you get to them. It's also possible you may abandon the quest and continue to do this, but I would be unsure.
The reason this is good Werewolf exp is because the monsters count for some reason. And Werewolf is leveled by killing things in Werewolf form as opposed to like a normal skill.