While the shutter shading issues of the D750 don't plague every body, Nikon's recent service advisory (i.e., recall) does apply to quite a few of them. Many might groan at the thought of sending in their workhorse or even backup D750s, but the truth is that this may be a huge blessing in disguise.
When I heard the news and checked my serial number after the recent expansion of the D750 recall, I began boxing it up the moment it came back as "affected." I threw my NPS number on the front of the paperwork and requested expedited service, and just last night UPS left it on my building's doorstep (outside the gate, but that's a separate issue).
What I didn't do was ask what the fix was. I didn't have the time during the week then, but I took a moment today to call Nikon and ask what they did. The representative on the phone told me they replaced the entire shutter mechanism: new shutter. This isn't something that can be fixed by tweaking something or adding some tape. I have a brand-spanking-new shutter in my camera — a body that I bought right when this came out.
So, for those that are affected, this comes at a perfect time. While some affected bodies aren't as old, many are starting to get well into the realm of high-mileage. And today, a good chunk of the D750 owners out there can start fresh with a new shutter, clean sensor, and full system checkup with round-trip postage all at no cost.
I'm not saying we should all pray for or thank Nikon for manufacturing issues (and it certainly hurts Nikon, which I'd love to support and keep in business as much as the next brand), but all of a sudden, waiting a week for your camera to get back doesn't sound so bad. You might just want to take advantage. You can check your serial number and get service here.