When in Vampire Lord form you can't access you're usual spells or abilities we probably won't even have inventory access itsn't that enough of a restriction?
Yeah but look at all the spells you have as a VL; Night Cloak - bats feed on enemies in melee range, Mist Form - turn into an invulnerable cloud of mist while regen health, magicka, and stamina, Corpse Curse - paralyze foes with a magical blast, Vampire Grip, Summon gargoyle, Raise dead. With all these powers along with your claws anything thats in melee range would be dispatched easily. Then, you can just pull anything out of melee range to you with vampire grip. Compared to werewolves, vampire lords are gods. Plus seeing as how normal vampires are no longer attacked, there will no longer be any drawbacks to becoming a vampire and will just be an OP form. At least, forcing players to be stage 4 in order to transform could keep players from spamming it.