I agree Cooper has nearly nothing good to say about the Shermans, he makes them sound so bad it's a wonder we won the war at all.
I do agree with Cooper that the U.S. should have built more Pershings than it did instead of relying on old technology SHermans. Politics are what got in the way as usual.
It reminds me of the japanese zero. It started out as a good plane but the japanese never upgraded it or modified it significantly as the was progressed. By the end of the was the zero was very outdated the same way as the Sherman was.