I posted this in the wrong section so reposting this here. Sorry!
As I mentioned in a separate suggestion, it is currently difficult to obtain high tier items. While I think they should remain harder to come by - particularly in the early to middle game, the present means of obtaining them, i.e. waiting for them to go on sale in a town, is not particularly satisfying.
I'd recommend allowing captured characters such as bandit leaders and nobles to attempt to buy their freedom by offering you their weapons, armor, and/or horse. I think the likelihood of this occurring should be somewhat low (20% chance). In addition, this should be tied to character traits by either being more likely to come from nobles with certain traits and/or impacting their traits and reputation.
When this comes up as an option, I think you should also be able to take all of their equipped items by force but this would damage your reputation among all nobles in their faction (and perhaps all nobles in-game with certain traits like honorable). Viking Conquest allowed you to do this so this is not an original idea.