does sion need buffs

everytime i play sion i feel useless, if you go full tank you do zero damage, if you go full damage you die instantly, and there isnt really a inbetween. i know he is supposed to be an unstoppable tank but his passive is the most useless thing ive ever seen. it always seem like you get super close to killing someone and then you die or you run out of speed boost. he should probably have unlmited speed boost to be honest because he is so easily cc ed. idk old sion just seemed alot stronger.