I think it would be nice if there was a feature which allowed players to yell out commands such as "Follow Me" or "Stand" or "Charge" so that their follower could react even if he is out of reach. Ever had your companion aggro by some terrified goat and run after it? Well, all you'd have to do is press a button and he'd come to your side. No need chasing after him. It would also give you more control in difficult combat situations. For example, if you command your follower to stand he will be forced to use his ranged weapon instead of closing distance.
