Anyway, the 6D's cross sensor has a higher sensitivity than all other models mentioned.
I realize the AF seems to have been deliberatively crippled (and overly-so!), but for shooting portraits and candids and casual soccer of my kids, I really don't need the pro athlete or bird-in-flight AF.Crippled or better, depending on your needs. The 6D is supposed to focus in even lower light than the more expensive 5D3. For some photographers, that may be a significant advantage. Of course it will not be as good in other ways. I'll be very eager to see how well the 6D's AF performs generally.
By the way, everyone says "crippled" about less expensive cameras, as if to suggest some bad intent on the part of the manufacturer. "Crippled" suggests that they start with an excellent AF system and then damage it terribly. But less expensive cameras are less expensive for a reason — less goes into them. The lesser AF system is designed for a lesser price, from initial concept to production.
Manufacturers have to differentiate their products somehow. We do it as a photographers. We differentiate our products according to size, hours, materials, etc., and yet we don't say our cheaper products are deliberately crippled.
Whilst I will reserve judgement on the 6D's AF system until we seem some credible reviews, I think that people are using words like 'crippled' because the 11 point system with but a single cross type sensor (however good that might be), is perceived to be inferior to even the 9 point, all cross type system on the 650D. The D600 uses the AF system from the D7000; I think that people were expecting some version of the 7D's 19 point (all cross type) AF system on the 6D; when you are disappointed, you tend to use emotive language.
I think it's fairly clear Canon had a specific type of photography/photographer in mind when they designed this system. Namely people who don't shoot many fast moving subjects, but need to focus in all kinds of light. Portrait and landscape are of course two that come to mind. If you look at it from the perspective of that type of photographer, the -3EV center cross-type should be outstanding and clearly an upgrade from the 60D/650D, since the other points almost don't need to be there (even on the 5D3 the most precise points are in the center). The sports/action/wildlife photographer is right to say this system is unlikely to be good for them - and get a 7D or 5D3. I realize this isn't what a lot of people were hoping it would be, but for some this may be just what they needed (without the expense of the 5D3).
The d600 looks like it's more of a sports/general use camera, with a higher bust rate, and more AF points (even if all the cross type are stuck in the center.) The down side is, it won't handle low-light as well. Since I shot a lot of strobist stuff at dusk/night, the 6D looks like it could be the better option. Although for others the d600, 7D, or 5D3 may be the best option for their type of photography.
We do have cameras that do (almost) everything very well, the 5d3 and the d800, but you have to pay a lot more for that sadly - and that's just the reality of the market.
Should Canon have put the 9 or 17 point all cross-type system from the 60D/7D into the 6D, it's hard to say. On one hand they would have made tracking better, but on the other, it wouldn't be as good in low light. Only time and the market will tell if this was a good move or not.