Must... be... given... no... challenge.
From everything I've read in this post, the spell works exactly as intended. It adds a decent amount of damage and a bit of a lifetap. It costs more power to do so but then, that's where the challenge comes from. Do you spam all your abilities or do you actually choose which ones to use in a fight? If all spells were made to be super efficient, we'd have a bunch of button mashers running around in EQ2.
I, for one, am much happier with being given choices. In some fights, I'll use more of my dmg dealing abilities while in others I won't. Again, don't forget that we also have to work in the Combat Wheel which so far, hasn't been all that successful with all the button mashers out there.
Take the time to learn which of your abilities are "must spam" during combat and which ones are situational. Even if they are damage dealing abilities, it doesn't mean that they "must" be used during every combat and as soon as they are reusable.
Guln
24 Dwarf Shadowknight
Mistmoore