I'm not sure what you mean by turn rates, but I think the response of units can definitely be improved. Right now, it seems like the units would freeze for a moment then respond to formation orders. When retreating, many units struggle to turn around and run before they are killed by a shower of enemy arrows. There were also instances when an enemy spearman was just waving in the air and the cavalry unit on 30% health that was already some distance away from him just dies suddenly.
Furthermore, I noticed that some units, especially cavalry and siege, have acceleration. If you order them to change direction, they stop themselves, then take a long time to rotate itself to the direction you pointed to, then gradually accelerate towards there. I think the acceleration is completely unnecessary; just let the speed be a step function and that will feel much smoother. If you must consider physics, then perhaps the unit can choose a curved trajectory towards your point, given its current position and momentum. A curved path is how a real human would walk if you wave at them from across the street. The rotation of units would ideally be instant, i.e. the angular velocity is very large. This will cause less stuttering as described above and less miscalculations, meanwhile improving the smoothness of the gameplay.