@ Riot: Mana Siphons

Would you ever consider making another champion that siphons mana from their enemies after you removed the ability from Kassadin? Or did you feel it was too unhealthy of a mechanic to keep in the game? I think something working like that but similar to Swain's ult would be cool, where you didnt take away a giant chunk at once but rather slowly over time during teamfights. It would have an interesting impact on the game, where staying in extended fights would slowly wither away the enemy team's power, but wouldn't be just instantly making them useless. This type of ability might go well on a tank type champion who can duke it out in extended teamfights but doesn't have much damage potential on his own. Either that or a tanky support. Lemme know what you guys think.