Possible idea for a new Kassadin Q

I saw Kassadin on the list of possible reworked champions in the assassin update, so since Kassadin was my one time main, I thought i might put down an idea I had that I think would make him more viable. I feel that the current shield that Kassadin gets on his Q is pretty useless. It lasts for only 1.5 seconds and is easy for the enemy to play around. Kassadin is known as the anti-mage and I don't feel that his Q does enough for him. My idea is that instead of giving him a shield, it would steal some mr from the opponent and give it to Kassadin for a short duration. I feel this would help against the popular picks of Vladimir, Swain, and other tanks and would emphasize his anti-mage concept. What do you guys think about this? Good? Bad? Any other changes you guys want to see? Feel free to comment and let me know.