Gege's error was to bring him back (probably under pressure by his editor) up to that point he had managed to come up with arguably one of the most interesting versions/developments of the whole "character is so overpowered that he's basically a god amongst men" in recent manga along with pic related. The idea of having him and having the bad guys have to come up with some contrived way of temporarily taking him out of the picture because they know they can't do shit with him around and can't ever beat him was really smart and probably the highlight of JJK's writing.

A shame he folded and brought him back for some powerwankery and fanservice.