No turncap would make movement irrelevant. In Warband, part of the reason why you could dodge attacks, or force them to glance, was because of the more restrictive turncap (and the tighter swing arcs).
I have included a helpful demonstrative video for you:
I agree with you that Bannerlord's combat is simpler than Warband's, particularly when it comes to things like attack angles and movement, but the freer turncap is one of the things contributing to that problem.
In Warband the situation was a little unique, as while holding an attack or block you could only turn relatively slowly but when changing input, ie. holding an attack and pressing block, you would almost instantly turn in the direction you moved your mouse. This meant that while you couldn't spin around as fast as you could move your mouse while holding an attack, you could instantly turn beyond the turncap to block incoming attacks.