Levitation, teleportation, open, lock, sanctuary, waterwalking, jump, slowfall, drain/ damage skill/ health/ magic/ stamina, and everything else I have forgotten that has been removed for no good reason.
I'm playing my vampire without Illusion or Destruction and focusing on Conjuration, Alteration and Restoration. I'd like to be able to conjure something that's more vampiric that a Flame Atronach.
They should have all kinds of spell types for different types of vampires. Personally I see more illusion than anything, invisibility and calming effects so you can go in closer to bite and trick your prey.
Perhaps advanced telekenisis on enemies? Necromantic spells, or other conjuring spells, such as summoning a guardian of Soul Cairn? Plenty of potential for new "blood" destruction magic, and considering the Vampire Illusion boost, I wouldn't be surprised if there were new illusion spells.