It will be even messier if Turkey is part of the EU when this takes place. However I think this should resolve itself before that happens as it doesn’t look like the EU is letting Turkey join anytime soon.
It isn’t certain what will happen with regards to greater Kurdistan (Kurdish areas in Iraq, Turkey, Iran), although it could certainly get ugly there.
Any Kurds in Syria? I’m not sure, and if so what that would imply as well.
Nevertheless, this goes back a long ways to when the British occupied Iraq (taken from the Ottoman Empire in WWI if I am not mistaken). It is always a difficult thing to go back to the pre-colonial (and pre Ottoman empire) nations and boundaries as often they were not clearly marked or identifiable. Besides, there is oil in N. Iraq…and everyone wants a peice of that!