What some photographers are trying to do, including myself, is duplicate, in the 5D MK lll, the sensible feature found in the 1-D series, and 5D MK ll. When using my 1-MKll bodies, I am able to benefit from a nice plain screen, use Servo AF, and in dark conditions see my selected AF sensor briefly light up. A very useful feature.
I don't want a viewfinder filled with dozens of lit up AF sensors to see what I'm focusing on.
The 5D MK 11 has the helpful feature, but I never liked having 9 little boxes always on the focusing screen.
I'll test AI Focus to find out how well it performs for sports and active subjects.