Go to CR forum for Images 1Dx, loads of sharp images.
The fact that you tried 2 Bodies & same issue might indicate the issue was your set up, rather than the Bodies. It hasn't seemed too difficult getting sharp Images, be aware that if your shooting RAW you will always need to apply some level of sharpening in Post, I don't shoot Jpeg so not sure if the same applies, but I suspect it would, especially prior to Printing.
I think the current service notice re the lubrication/focus is something that works it's way in after some use, rather than from the Factory.
I use 2 1Dx bodies, both affected by the recall/ service notice, but to date no issue, I'm sitting in the Lounge at Dubai Airport on the way to Tanzania so hoping the issue stays away for 6 more weeks.
But if your Happy with the 5DMK III, go have Fun, you have an exceptionally good Camera either way.