Every time a new model comes out, we have a flurry of posters with soft images.
In some cases, the camera needs to go back, but in most, the photographer needs to spend more time with his new camera.
When I received my 7D, one of the first to be shipped, I took it out and got s lot of oof images. After reviewing my settings, I tried again, and the results were much improved. The third time, I started to get consistently good results, but I did a lot of checking exif's on the bad photos in between.
With my 5D MK III, I did a AFMA on my lenses, then I set it up on a tripod, and took a few carefully controlled shots which were all razor sharp. After that, I knew any soft images were my error, and sure enough, they were.