I don’t need 10fps but I sure use it on my 1D IV all the time for wildlife and sports.
It is very nice to have.
I think the 5D III with those specs is still a great camera for still life work. I doubt the AF system will meet the requirements to match the performance of the 1D's with action. Even if they use the 1D's AF system I bet canon cripples the AI servo mode so it will not compete with the 1D X. It will probably not have the same options available for customizing the AF system. But if it can at least be as accurate as the 1D series it is a big upgrade IMO.