That's fair then. The only problem I have is that I've seen what happens when a Wizard runs out of Mana: They die, quickly. If enemies have limited mana, what stops a Warrior -- or any other quick character -- from running in circles until the enemy's Mana is depleated from throwing fireballs, then whacking them a couple of times to kill them? Perhaps both skills are needed: Magical Seive and Mana Restore. Enemies can have levels of Mana Restore so that when their Mana runs out, they can replenish slowly, leaving them vulnerable but not completely defenseless.
Just to clarify, is your skill meant to steal Mana from an enemy and add it to your own, or just to dispel their Mana?
Perhaps another spell could be something similar to the D&D spell Silence. Silence prevents any sound happening within a 15 foot radius of the target, making any spell requiring speech impossible to cast. Perhaps Anti-Magic Sphere could block a target from casting for x seconds?
