If Diaw is a full-time SF, we wouldn't have so much trouble at all. Boris is a very versatile player with a lot of talent, he probably worths 9M after all. But his versatility also means he is not particularly good at any position, sometimes making it difficult to utilize him.
It is true Diaw can play SF, and he does well in certain matchups. But overall, he is limited at that position, especially not the type of SF we need to win championship.
Offensively, Diaw is neither a good shooter (inconsistent in distance, no 3p accuracy at all), nor a slasher (seldom drive in and finish above the rim). Even when assigned to SF job, he tends to post up and finish by short range jumper or layup, which is clearly not necessary for this team, we have Shaq and Amare.
At the other end of floor, Diaw is not a physical defender at all, lack of mental toughness, a bit slow to guard fast and skillful SF scorers. We all know what type of role Bowen and Posey plays, and how important they were in their teams' championship run. Barnes is the right type, we hope him to do something Diaw couldn't.
Talking about point foward, we already have Grant Hill, who is clearly a better passer at perimeter. Must be aware, Diaw makes a good number of APG, but a large part of them was passing out of post. And, we certainly prefer to find a true PG to backup Nash instead of using 2 point fowards.
Obviously, there were enough reasons for D'Antoni to pick Hill as starting SF, and use Diaw mostly as PF/C when go small. The same reasons we signed Barnes.
We don't know what's in Porter's tactic book yet, so Diaw's future here remain a mystery. Can Diaw learn something over the summer? Can he adjust his game to fit the team's need? Can Porter find a way to fit him in properly? We certainly hope so, saving us the trouble of making a trade.
It is not we hate Diaw, or underestimate his ability. We must organize our team to the level of perfection, it got to be deep and balanced at every position. It is all about what is the best to do for us to win a championship.
For now, it's crystal clear we r open to trade Diaw as long as it's a right deal.