Regarding Energy Drain on SCH, I don't think it needs much of a change to work without dealing damage. Hell I'd like a change on SMN that gave them an ability they could use without needing an enemy around too, and ED is an ideal button to replace on them as well. I think keeping the MP restoration part of it would be fine for SCH. Maybe have it improve your next spell's potency as well and call it Focus, perhaps?

Though for SMN in particular it would need to be on par with Fester to be worth using, so SCH and SMN would likely need to diverge from that one ability into their own versions.