The damage resistance, the sneak speed, the magicka/stamina recovery, the massive buff to Drain Essence, Elusive Mist is amazing in group PvP to avoid dying.. all around Vampire is far superior for a Sorcerer. I never liked the idea of being a vampire, but it is so good I have no choice really.
WW is 100% completely and utterly useless come the new patch. It's only for role players, people who like being a wolf and don't mind gimping themselves. Basically you lose an ultimate slot and gain 15% stamina recovery. As a vampire you gain so much more without losing anything.