The Whistling issue on 09 Traverse is not an issue with the door. At this moment GM is trying to figure out how to rectify the issue. Swapping the doors is unnecessary and if there are any problems with that door in the future it will not be covered under warranty[not to mention what intotheoh mentioned before]. Although it is annoying that your new vehicle has a whistling noise at certain speeds, it is not an actual problem with the vehicle. If anything it is most likely an issue with the aerodynamics of the vehicle causing wind to possibly get caught up within the side view mirrors and create a whistling sound. GM has not come up with a fix for this issue and therefore GM dealerships cannot take any steps to fix it, as it is a warranty issue. If they did start doing things to the vehicle they would have to cover the costs... and if anything they did to the vehicle became an issue later on, they would also have to eat the cost[and take responsibility] of that. In fact it would be unethical for them to do any unauthorized warranty issue work to the vehicle. We are hoping that within the next month they will figure out what is causing the whistling and send out a bulletin to GM dealerships and service centers instructing us how to fix the issue. The fix might be something as simple as the sunroof guard which was mentioned earlier.....
PS- This is not just an issue with the Chevy Traverse, but all of the GM models which are of the same style[Buick Enclave & GMC Acadia]
So as for the complaint of GM service at those dealerships- they're only doing their job, and one cannot make a statement generalizing the customer service of GM and their dealerships. While their is a "standard of excellence" which we are supposed to uphold, it depends on the specific dealership to make sure that the standard is being met.
I hope this helps to explain what is going on and why they can't replace the door.