As far as melee is concerned, if movement was allowed during WS's (at all times meaning free movement) there could be a penalty. For example if you move, but are facing the target you will have maybe a 50% accuracy reduction. If you are moving and face away...you flat out miss.

Other than that, I can't think of anything else right now. Someone else had mentioned something in this thread about it before I'm just too lazy to look back :P.