I call bull to this as well. While the 6d does suck...the mk3 is an amazing camera --- and yeah, it is what most users asked for. Target for that was definitely wedding photogs who felt that the IQ from the 5d2 was as good as it needed to be, but desired better AF, better build, and expanded ISO performance - we got that and most who use the mk3 for weddings are joyful for it. No, its not a giant leap for studio and landscape shooters - but those users need different tools anyways. Yes, the d800 is more suited to the studio. And unless you have another body at your disposal, its not the best wedding camera either (you lose the advantage of FF because to get smaller files you have only the option to crop your RAW's). This is where the idea of $$$ goes out the window because people will line up to tell me memory is cheap and so are computers...just buy more CF/SD cards and more harddrives and cloud space and a new computer to handle the workflow... oh wait, I thought that $500 was so huge that one could never ever spend that much more? Yes, if your workflow consists of more time spent setting up the shot than shooting, the d800 is impressive. But I don't even want to think of the added costs of using that on over 3000 wedding shots.
Now with that said -- the 6d is a totally different beast with seemingly no real plus's to it (its a FF rebel at xd price competing against a d600 with actual pro features at the exact same price point!). I believe it will be a flop because ---
1) there is nothing wow about it
2) the price is still steep for rebel upgraders (especially when you factor in that EF-S glass is useless in the canon FF universe - at least on nikon you can still use it, albeit in crop mode --its still usable at least and not something you HAVE to sell because they won't mount on canon FF bodies)
3) Weak AF is the reason many rebel users opted for the 7d over the mk2 - (more options, less cost, more glass options because you have EF-S options) if you have to sell your glass and by new glass anyways, nikon becomes a whole lot more alluring
4) Weak AF again - this FF should be a nice upgrade path for current 7d users. Other than gaining a bit of low light advantage, this body is a step back (think of how many replies to all these threads have beat the drum of why not just have a version of the 7d AF in a FF body at a middle of the road price ---this isn't people wanting a 3500 cam for 2000...its people wanting a 2000 cam for 2000!!!!).
5) Oddly enough, taking that pop up flash away kind of ruins this camera from the perspective of it being the FF upgrade path for rebel users.
6) it isn't attractive to professionals who may very well have wanted a valid option at this price point as a backup body.
That's how I see it with this camera. If nikon had not released the d600 with the spec list it has, then, while no one would be excited about the 6d no one would be so hateful of it. But they're both here! And unless the d600 fails in many areas (IE, yeah, 39 points, but if they are all in the center of the frame its no real big help, and how does it perform, fast and precise or slower and less precise- and ISO, does it rock at 100-800---but fall off after that - vs - will the ISO on the 6d be on par with the mk3, while boasting less AF points, will they cover a larger area of the frame, and will any of them be any good except for the center one?). All we have now is what we see on paper, and the paper leads to the d600 winning this round. The real test will be when we see the 2 compete in the wild.