Manaward is sometimes on thing thing called a cooldown.
@Zyneste It wasn't usually in dungeons. It was in 8-man raids. Mainly in the Omega fight. And to be fair, I wasn't always depending purely on the Drain for this. My Paladin friend would also Clemency, but it often took both to keep me alive when healers were being shitty, but there were numerous times I got myself up just enough to survive a raid wide aoe by spamming drain beforehand. With competent healers, of course, I never cast Drain. Like I said, I'm perfectly fine with it being removed, but it was fun to make use of in those rare occasions where it was actually useful.