passive: seems fine, decent scaling. it looks ok to me.
q: a poke that reduces armor, its fine.
w: a nuke that heals? :O it just might work! I like it anyways. heals aren't too much, and its a nuke, so damage seems about right. but I feel that this and your poke might be too strong together, maybe nerf the ratio on your q just a touch.
e: nice, just a little fear with slight mind control. but, how long does it take before the target automatically stops? because essentially, you could make them walk all the way back to their base if there is no specified duration for making them move.
r: this, I think, is fine and requires no change. very punishing to targets that hide behind the tank.
overall: I think this champ really fits the role of anti-tank. however, this could also be a little too strong in certain cases. I gave a couple suggestions, its up to you to do what you wish.