I'd like this too. It can be a bit of a mess trying to click on a character if they're in a melee.
I'd also like to be able to cast abilities on the enemy portraits in the action queue. I've had one time where I couldn't target an enemy even though he was standing in the open.
You can cast spells/skills using the portraits in the action queue during combat. Minor Heal can not be used on the caster that way, but can on the other main character or a companion.