I feel like this could be a good exercise take a previously made script and rewrite it or take scenes from that script and rewrite them.  Don’t publish obviously but just read the script or scene and try to rewrite it.  

Why? Is my question here. If the script has already been filmed, one would assume that the script has been reworked to the best, or at least near the best it can be. Wouldn't it be more useful to take an unproduced script and see if we can make it better?