I personally feel like Hirelings are a fairly incompetent bunch. They don't use abilities that they have without your direction, they don't cast buffs on themselves, and they often just stand around and do nothing while everyone dies around them.
For instance, Cleric hires will sit and stare at a dead player's soul stone and won't cast Raise Dead until told to do so. Not a problem when patching up after a fight when you have time to stop and tell them what to do, but in the middle of a fight you can't always afford to stop and hold it's hand. This problem get's even worse when some Favored Soul hires don't have Resurrection on their hotkeys (You expect me to believe a 20+ FvS doesn't have Resurrection?).
Another issue with the hires is that they have almost no will to live. If someone casts Acid Rain, the hire stands there waiting for death. These issues combined with some other problems make Hirelings a hassle nine times out of ten. I would like to see hires be updated to be at least semi-competent. Maybe at the level of an experienced beginner?