I agree with Korolev. If he gets a coach that could teach him tactics, he'd be a much better player.
Yes he would, but even then, the "next Safin" predictions were always off. He should be a guy in the 60s and 70s in the ranking, but I don't see him being more than around 20-30. Even with better tactics, he's still a one-dimensional player with an average serve and below average movement. He just needs someone to harness what he actually does well and apply it better.