As I said "Between Aetherflow, Energy Drain and Lucid Dream" it is rare to run out of MP. I wasn't trying to imply that Energy Drain is a preferred action. There are times you need to rebuild MP quickly such as after dying where Lucid Dream and Aetherflow are on CD. ED fills this need. The key point I was trying to make is MP is not that restricted of a resource as there are ways to rebuild it.
