I just ran a quick search about it in this thread, but i found nothing, so... I don't know if i'm the only one in this case, but i find the honor feature to be less interesting than it should be. If i'm not wrong, its only purpose is to increase relations with honorable lords, and ease the courtship of honorable ladies. The other side of this purpose is to prevent the player to play the "easy way", burning and looting villages, betraying people, etc...
However, what if someone wants to become a Rogue Lord ? Correct me if i'm wrong, but for now there doesn't seem to be any positive effect of having a bad honor rating (which is, actually, a typical feature of rogues) ; and since being a rogue in Mount&Blade is already quite a challenge, i think this should be both useful and more realistic.
So i've thought about a few things that could enhance the honor feature, although i've no idea of the difficulty to implement it into the game.
1) Bad honor should give a boost about everything that is related to plundering : after all, looting dead corpses and harass poor peasants is something unhonorable men get really used to in Warband's world... On the other side, maybe a good honor rating should give a penalty about it.
2) When it comes to "forcefully recruit villagers" and "recruit volunteers" : the first should be enhanced by a bad honor rating, whereas the second should get a penalty. The same goes for good honor rating, except the other way round.
3) Bad honor should inspire dread, while good honor should inspire goodwill among your people ; so taxes should get a bonus in both cases, wages should also be less important, and whereas an unhonorable lord could possibly set high or very high taxes rates with less penalties than an honorable one, he would face more desertion, banditry, or even rebellion in his lands than an honorable lord (which however cannot permit himself to set high taxes, or raise funds the way a rogue lord can if he wants to uphold his honorable reputation).
4) Bad honor should also give, as a king, a penalty in diplomacy : no one wants to trust a rogue lord for an alliance... On the other hand, it should be much easier to "squeeze", as it is said, the other realms by threatening them. Good honor in the other hand should give an advantage in diplomacy.
5) Prisonners should more willingly be part of your troops when you ask them ; lord prisonners should try to evade less, both if you've got bad, or good honor.
6) Possible to imagine some more interactions between you, and your companions, as well as you, and your lords.
7) Possibility for lords of high honor, or highly dishonorable, to set exceptional taxes for fiefs, as "war effort" or "wedding effort" and so on. They could be collected the same way you collect funds a village owe to a lord (sometimes one can get a lord quests, where one has to collect taxes of a village).
These are examples. I don't know if they're worth anything, but the basic idea is to improve the honor concept, which for now seems a bit as an empty feature to me, with very few profund gameplay implications.