No, not high speed sports action but FWIW in the discussion down the page you linked Scott says (3months ago) in answer to another poster there:-
Scott Kelby Mod > andrewccm • 3 months ago
Hey Andrew -- The 5D Mark III takes great pictures of whatever you aim it at, for sure (I have one myself and absolutely love it). Like you said, it's not optimal for a primary sports body, but I did use it as a secondary body for a game, and while the fps and buffer killed me, the shots it did get were beautiful. I just need the crutch of something faster.
So perhaps horses for courses and hence my comment that a 5D3 and 7D2 are complimentary in the kit bag