5D3 is 'better'...but not worth the price difference for a non-pro unless the price is not an issue to you.
6D image quality (outside of DR issues) is outstanding. That's kinda what it's all about. For wide DR images, shoot bracketed.
White balance is a non-issue IMO. Use custom WB or shoot Raw and fix in post. If you don't do any PP, get a P&S.
The 6D is not aimed at professionals or wannabe's, though it may be a suitable backup body for some pro's. YMMV.
To some, an articulating LCD seems.....amateurish. Until you try it for a while. Perhaps this was the tradeoff for wifi.
Focus points - it still has more autofocus capability than my old Nikon F2 did. If I made a living shooting sports or BsIF I'd go with the 5D3. But I don't and I won't. I can afford but not justify it, the price difference goes to glass.
My feeling is that the 6D was aimed at the higher end amateur market. More precisely, those who are already Canon DSLR owners, and frankly I think Canon hit the mark.