I'm not saying that Turkey would crack down on Kurdish citizens, I'm saying its Kurdish citizens may revolt. Basically a Kurdish state would threaten the stability of both Iran and Turkey.
Also don't you see a problem with the middle east being split into two strongly opposed blocks? Currently Iraq is a buffer, a mixed Sunni/Shiite state that if it succeeds will greatly help peace in the middle east. If it splits then we end up with more Shiite Sunni wars.
Also there has been progress in Iraq, the Iraqi government is gaining more and more control, it has a better police force and army than it has had since the fall of Saddam.








