Just to play devil's advocate:
I like the order system the way it is now. In fact, I don't think you should be able to give orders at all if you are too far away and out of sight of your men. Perhaps more complicated orders could be given (such as 'move over to that hill and give covering fire') but you should have to personally walk over to the guy and tell him (in real time, no pressing the 'f' button to pause the game, so you have to pay attention to what's going on or you get a spear in the back.) Your guys will have been fighting with other people (if you rescued them) or be complete novices (if they're peasants), how the hell are they immediately supposed to pick up what you're trying to get across if you're halfway across the battlefield telling them to 'move to that hill, going through that valley there but avoiding the forest, and when you get there have the archers stand at the top and the infantry screen them. Oh, and if anyone comes within range as your moving.. etc. etc. etc.' Of course it would be great to give detailed orders in the midst of battle, but it's just not possible unless you're physically speaking to them.
Maybe before the battle you could assign relatively simple commands to a series of gestures or horn sounds, something simple like 'move around the left flank and attack' or 'take out those f*ckin horse archers', something you could change depending on who you're fighting against. The way I see it is like that bit in Braveheart (freedom!) Where Big Mel tries to get the cavalry to charge by signalling with the flag. This gives you a few tactical options without the usual Medieval Personal Radio Receiver b.s. you get in games like Medieval Total War. And waypoints should really not be implemented IMO, too much micromanagement. Trust your guys, they know what to do! (sure.)