Cavalry only able to turn 90 and move, or turn around to prepare for a rear charge doesn't fit with the description or depictions of bow armed cavalry, eg Russians are shown riding and shooting backwards at Poles, and described moving backwards and forwards to shoot like Tatars (of course Tatar cavalry have the same 'stuck in the mud' problem

It would be a simple change, already playtested in FOGAM... any chance of throwing cavalry a bone...