It really comes down to each person's needs. There is a difference between annoyance and necessity when it comes to 100% viewfinder. For non-professionals you guys have the luxury of taking your time and cropping the image later in post processing. Try cropping several hundred pictures a day. It slows down turn around time to customers and basically adds more costly editing time especially if you are paying someone to do it.
There are also plenty of times when I don't even have the luxury of editing my pictures before they are printed and handed over to the customer. One company I work for prints images on site so I have to get everything from white balance to cropping exactly the way I want it. That 5% missing in the viewfinder can make a difference because sometimes you can get the edge of a light poll, trash can, etc in the picture that wasn't in the viewfinder and for fast pace events like sports photography there is no way you can review each image in the LCD to check for problems. You just review a few of them and hope the rest are good.
I do agree that for a majority of people the 95% viewfinder will probably not cause too much of a problem, but there is a reason why just about all "professional" class cameras have 100% viewfinders. We don't always have the luxury to post process especially if you work for a company rather than your own business. Considering the price of the D700 I would categorize it closer to professional class than prosumer, but like I said not everyone will be affected by the viewfinder so for some it's a deal breaker and for others it's not.