I've heard some people said that the M4 Sherman (and by extension the Grant/Lee) was tall due to the use of the radial Continental R-975 engine, which had a large circular cross-section. But I've also come to notice that the much shorter M18 Hellcat also used the very same engine.
Another pattern that I also noticed is, tanks with rotating turret basket/floor of the era like the panther also had similar height to the sherman (which had a rotating turret floor/basket), and the t23/25/26 prototypes had to forgo turret basket to achieve the same height as the T-34 series which lacked turret basket from the onset. And when the later Patton series tanks received their turret basket, their height went back to the towering 10ft/3m, around the same as the Shermans and Panthers, much taller than their t25/26 predecessor.s
So is it true that the Sherman was tall because of the radial engine? Or was it due to the use of rotating turret basket/floor instead?
Good question and something I never thought about.
All i can add to the conversation is that in my researcher days, I mostly talked to American and Canadian M4 tankers from late war campaigns in Italy and Germany. What they thought of the height of the M4 was often a question I asked. The concensus was no one really considered the height of the M4 medium at all. One veteran thought the height disadvantage was a afterthought when comparing the M4 to other successful WWII tank designs like the STUG III and T34. Vets had only good things to say about the spacious M4 interior, and reliability.
I would check out if Zologa has anything to say about that in his books. could probably email him and ask if you can't find it. He's a true tank enthusiast and would probably enjoy the question.
From what I've read and heard from experts is that the primary engineering concern with the M4 was reliability and ease of production. So, to assume the designs height would accommodate the relaible engine makes sense. As for the basket, I don't have any sources on me, but if height isn't a concern why not design the tank around the basket as well? Also interesting to note French tanks like the b1 bis were also tall, so the height wasn't extraordinary at the time.