Would it be good if when you ordered a follower to hold position they would still shoot at enemies, or in the dog's case attack enemies that come close to them? That way you could position a companion to cover you from a high point, or leave the dog if you felt he was going to give you away. Then if you got into trouble you could fall back to him and he could attack whatever was chasing you.
As it stands now a companion with a hold position order will not take any action at all. I found this out when I asked Preston to wait at the top of some stairs in a subway tunnel why I snuck down to scout ahead. I was soon mobbed by ghouls so I ran back up to him and he just stood there while I got beaten to death. I lamely tried to select him and order him to attack but it was impossible while I was getting pummelled. The whole scene was quite pathetic really.
All the ways I've stuffed up an attack and got killed this was the most frustrating, but funny.