Nash was defensively challenged, Scola is on a different level. He's the kind of guy that saps the energy level out there and brings everyone else down near his level. Or, at least, that's what I think I see. I don't think he's quite as bad as Warrick but I'd put him below Beasley (defensively only, he's far better than Beasley all told) which is a scary thought. He seems to have less impact on the second squad but when he's playing with the starters he really drags them down IMO. The good news is he manages to keep his plus/minus numbers looking decent because he takes out the whole squad with his play so his stats don't stand out.
Have you ever played the game with someone who keeps letting his man go, forcing you to chase the guy down. The crowd walks away thinking you're the bozo that keeps letting his man score and trust me, it wears you down. You get to the point where you figure why even make the effort to guard someone, your teammate is going to leave you exposed regardless of what you do. Jermaine sort of plays a one man zone too but he doesn't wander around and pick up some guy who's already being guarded 15 feet from the hoop. His tendency to stay close to the basket is probably what saves the team when he's paired with Luis as he's already in position to pick up the man Scola has abandoned.
And I really don't think I'm being all that unfair about him. If I am, it's only because I sometimes ignore the good things he does for this team. But, I'm convinced the bad side of Luis more than outweighs the good side and this team's best chance to get victories is to play hard especially on the defensive end. I think it's almost impossible to do that when Scola gets significant minutes.
Steve