I think if you're going to have idle party members questing for you on quests with choices to be made, the most interesting way to do it would be to have them make the choices one would expect them to make as characters.
Then when your pal, Ogdoff the barbarian, destroys half the village to drive out the thief, you can slap your forehead and go, "Drat! I knew I should have sent Harry the bard for this one!"
Not only would it encourage you to carefully pick who to send, but if you're a joker, you could send Dandof, the elf-hating dwarf off on a diplomatic mission to broker peace between the elves and the trolls, and then laugh as you find out what happened.
Then when your pal, Ogdoff the barbarian, destroys half the village to drive out the thief, you can slap your forehead and go, "Drat! I knew I should have sent Harry the bard for this one!"
Not only would it encourage you to carefully pick who to send, but if you're a joker, you could send Dandof, the elf-hating dwarf off on a diplomatic mission to broker peace between the elves and the trolls, and then laugh as you find out what happened.