To be honest I loved the WW in Bloodmoon. When you got the disease it was a curse and it acted like a curse. Skyrim's WW just take all that away and make it more like a WW Perk.
I've never played Bloodmoon, but I do love this idea. It would give a very dark side to Skyrim, create a bit of depth. They could do things like social and physical consequences for your character, once he or she is back in human form. And I mean something more then having to explain why you're running around Whiterun in nothing more then a shredded loincloth.

Things like your vision getting darker, your moral grounding shifting, or have the more evil kind of creatures become attracted to you.
Talking about which; I find there is a very dark side to the Elder Scrolls world in the form of those Soul Gems. Even if only the "evil" black soul gems can hold a human soul, I still think they skip rather lightly over the fact that you can use a creature's very soul to get your weapons to cut a bit better. It's one thing to kill an animal, it's quite another to use it's soul for your own convenience.
It was touched upon very well, I thought, in the Elder Scrolls books. But still I feel there's a lot of unused story potential there. Or maybe it'd raise questions which people wouldn't want to be bothered with in a video game?