I think every team needs a player like Turner. He is a player that can be the x-factor every game. It's not something you want from a starter, but as a role player off the bench, he's an exciting player to watch. He also fits perfectly with this team. Guys like IT, Smart, Bradley, and Crowder are considered to be the core of this team, and he is cut from the same cloth as them.
He plays a lot of minutes but that's only because he has the ability to fill in for different positions. I think the need for him diminishes as the team morphs into a contender. He will end up taking on less roles and his production will decrease, as will his value to the team.
Given how teams work and how the media works, people are only going to remember him contributing to a playoff team and forget about all the bad stuff. Look at Lance Stephenson. Of course you guys remember "Trick or Treat Tony". Some team is going to give him a better offer.