The concept image for the 6D AF is interesting. It's more wide-set than I anticipated.
The design shows they really managed to build the anti-5d3 af: no cross type sensor at f2.8+ ...
... this is ridiculous beyond belief, no way to give this a positive spin even if it's up to -3ev. I've shot for a long time with an analog eos620 with no cross-type sensor - the pattern detection simply isn't reliable enough if it's only one point.
From Canon's product page: High Performance Composing and Focus
Canon marketing says otherwise? Well, I'm not quite convinced :-p
Maybe it's another type of AF completely different from what we've seen so far? I'm going to give Canon the benefit of doubt.
What has me intrigued is that the 6D will use the same AF tuning as the 5D3 and the 1DX, where you can set thresholds for focusing based on how subjects move across the points. It's possible that they've refined the software to the point where 11 AF points are acceptable for most shooters (accepting that this is not a camera built for high-end professional sports photography).
It would also explain why the AF points are so tall and long - maybe this AF system is more concerned with how subjects cross the zones as opposed to moving into individual points.
Either way, there's no way to tell if it will work or not until its put into practice. I think it's presumptuous to assume that only a multi-cross point AF system could be reliable.
Having used the 5D3 at work quite a bit, that AF system was overkill. I would tend to cluster my AF points so I can reach each zone with one push of the trigger in any direction. I find it's much faster and more reliable to move the camera slightly while pressing the stick once while autofocusing, as opposed to walking the cursor across 63 AF points one at a time; but that's a workflow that makes sense for me shooting fast action street photography like protests, riots, etc. Other people are doing studio or product photography and would need more selectable points. Some are shooting sports and need more coverage. Luckily Canon makes cameras for that.