making a hireling cast a firewall is a SURE way to get him/her/it killed.
They need to preserve their own skin, even if it means running in circles, tumbling, blocking or jumping away randomly.
Some sort of "evade nasty thing getting too close to me" would be great for wizard/sorc/cleric hirelings.
I'd also like to see clerics refrain from melee attacking on defensive, they should only cast heals on defensive (or when told to on passive)
If I tell them to go attacking somebody then yes... or they're on aggressive THEN they can go melee.