6D with 11pt AF with one crosspoint?? I mean... wow

Good observation (about the D600 cross points).

To your question: no, focus and re-compose is too slow for me. I do not shoot sports and action (in the real sense). But when shooting the kids I usually have to compose, focus, check exposure and pick the decisive moment in less than a second before I press the shutter. If slower, the kid will already look the other way or stare into the camera.

Landscape is different of course, but then, I could do that entirely manually.