A slight thought on Theft of Vitae - is it supposed to work on super-naturals? The Sabbat shock troopers that uses the Final Death animation when killed returns a substantial amount of Blood points but are otherwise not feed-able. Most "true" vampires, those using PC vampire skins do not seem to return blood quite consistently however.
Also, is it possible to make it count as a violate only if the caster is visible? To me, it's of very limited in practice since it causes a masquerade violation - this makes it only practical in combat areas, and the very long cooldown means it will only be used once or twice throughout a play through - I mean, how often do you run out of Blood points that you'd choose to cast Theft of Vitae over say, I dunno, Blood Purge or attack with more conventional means?