Some of you may or may not remember War of the Lance, a strategy game by SSI set in the Dragonlance universe.  This was a spectacular little strategy game. 

In it, you had heroes, and you would send them off to quest.  They would not be available to your armies while they were questing.  A similar system would be fun, imho, where you can choose quests for them to go on, and they would depart and would not be available until they succeeded or failed.

A nice little feature they had was your enemies (AI or hot seat opponent) could send their heroes on their own quests, or send them out to thwart your efforts.  This added a nice flavor to the game and it felt appropriate that there was no direct control over them and their quests.  You just sent them off on their merry way and hoped for the best.  Of course, you could group the heroes together and spend resources to aid them when you initially sent them out, but that was it.

It gave you the feeling that you were sending them out on these dangerous missions for the cause of the kingdom and you might never see them again.  It was excellent tension.  If they returned successful, not only did you reap the rewards, but you had a morale boost.  If they failed, your morale was hurt.

I could see this type of system incorporated in your text based quest suggestion.