You have the flexibility to go for the spirited or swaybacked sumpter horses, that kind of thing.
But it is pretty annoying having to do a quest like that, carry up to 10 horses around as you go from town to town. with a quest like that, i'd rather not do it. but once you ask a noble for a quest, you have to do exactly what he says, there's no opportunity to turn it down. it would be nice if you could, especially if you are low level with no army, it's pretty hard to capture the enemy noble man or to track down the raiders...