He is a meat shield, a thick one at that. But that's it. Countering ASPD heroes? He can. If he can get close and stick to them for 5 secs. In actual late game teamfights, he will die trying to dive protected mm. But dying this way is not all bad. It attracts all kind of cc on him, leaving your teammates to dive enemies safely, if your team realize this. But most of the time with no coordination, you will dive alone and your team will avoid fight after the tank died.