These "new sensor" cameras like the 5D-III, D7100, D3x,D600,D800 are simply AMAZING tools. The first time I picked up a 5D-III with the re-positioned controls I thought, "God...this feels like a pro Nikon." Gone was that $389 EOS Elan body that the 5D Classic and 5D-II had. Gone was the old, clunky, 9-point AF. Instead, they souped up the sensor, beefed up the AF, and made one heck of a camera. The 5D III could easily have been named something else. It's whole new thing.
Back to the OP's issue: being disillusioned by Canon. I can understand that. The camera companies have products, and once in a while, other companies offer competing products that make Product X or Y seem "anemic", or "sub-par", or "non-competitive". Believe me--I KNOW the feeling. Nikon seriously lagged behind Canon for multiple generations. Right now, the 6D versus D600 is one specific, head-to-head area where Canon's design ideas are different from the direction Nikon went. The Canon offers wireless connectivity and direct uploading, which is something that many "techie" and social media photographers might like.
"We try harder, we're number 2, so we have to try harder." Nikon has been vigorously discounting and cutting prices, and has been inching upward closer to Canon in sales. Still, I think maybe the OP ought to give the 6D a chance. YES, it is a "simplified" camera, with no pop-up flash, no flash commander, and so on. But it's got a good sensor. I personally think of it as the 5D-II Lite. On the other hand, if he's really disappointed, he could switch brands. The thing is: a few years ago, a 6D would have been a home run camera; what is making it not one is 1) the 5D Mark III, and the Nikon D600 and D7100.
I enjoy the tools of the photo game. Camera talk is fun. There are many different options in today's marketplace. For the hobbyist with less than 5 lenses, I can see switching systems as being not that big of a deal.,