JCFindley, all the things I find compelling in the 5D Mk III (strong auto-focus, dual card slots, pretty high ISO with no noise, silent shutter mode) mean nothing to you because of what you shoot and the way you shoot it. The 6D has more pixels and a better monitor than the 5D Mk I, but otherwise I can’t think of much that would be an enticement for you.
They each have their strengths and weaknesses, as does the 1Dx. It’s simply a case of figuring out your needs and getting, or staying with, the body that meets them best.
Got to like a comparison that states lack of a pop-up flash is a weakness in both 6D and 5D!