He is definitely very dangerous and has the potential to do more then just tackle someone to the ground. He would have started punching Bret Hart if the other wrestlers did not stop him so fast. He should be in a mental institution. WWE would never hire him or allow him near a WWE event again.
I agree he does have potential, but that's not how crime and punishment works. You can't punish somebody based on what they MIGHT have done, rather on what they did do. As it stands, all this guy did was tackle Hart to the ground. Which is a minor assault. That, and given his previous misconduct towards a professional wrestler needs to form the basis for his punishment.
He definitely needs mental help in some fashion.