That's a nice advantage, depending on who and how the calculation is done, and since the advantage on offensive, rather than defensive, would indeed tilt highly in the direction of the M4. I understand the evolution of Armour very well and why design variant upgrades were made at every turn. I regard the M4 as OK for the day, but a "make do" from start to finish. I regard it's biggest advantage was the speed at which it was produced in quantity and rushed to the battlefield, like a tactical plan, an OK plan today is far better than an excellent plan a year from now. You could say, I may be prejudiced from being in the trade, so to speak, regarding all iterations of armor before as junk, knowing the drawbacks and shortcomings of design and function, having seen "the end of the movie" or latest design of the time, first and glad I never had to ride one those antiques. It's a skewed view, to be sure.
I could also add, as a young Lt, I had a 70 something year old friend, that liked to talk about tanks and tank engagements of world war II, as he was tanker in Patton's Army and he considered them junk.