Not wanting to sidetrack but i don't think the Sherman really deadends any more than the T34. Upgraded Shermans were effective in Korea and the Israelis made good use of upgunned shermans in the 60s IIRC. OK in a sense the T34 "led to" the T54 but it's a pertty distant relation.

Given what a rush job the Sherman was its amazing it did so well. I was going to say it makes you wonder what the Americans could have done if they had had time to design a tank properly, but then i thought of the M 60 and decided....maybe they work best under pressure?

Interesting tiger factoid: The Germans produced one additional drive train for every ten tiger tanks.

For a tank notorious for destroying its gearbox this is unintelligent. Just another reason why the Tiger wouldn't be on my list.