Feasts for me. We direly need feasts.
It served multiple purposes. Primarily it was a way to actually meet all the nobles of the land face to face and interact with them. It was a good way to build relations (in Warband if you fought alongside a lord and spoke to them after you got a rep boost, so fighting a huge battle and going to a feast made it easy to speak to all of them to improve relations), meet the eligible ladies of the realm and begin choosing your future spouse, and participate in a big tournament in which all the lords fought in to compete. If you won the tourney you could then dedicate the victory to the woman you fancy to build rep with her as part of the courtship system that we also direly need back.
In addition throwing feasts was a massive economic sink for the player as you needed to collect a massive variety of food, drink, trade resources like spices and oil, and all sort of things. The more you spent the more rep you got with your guests. In Bannerlord this could easily be a way to convert your stacks of gold into influence that can be used to further your standing in the realm.
And most of all... It just gave the lords something to do aside from fight. It was an activity to do during peace time and a way to celebrate large victories so that the AI didn't just keep going and steamroll over a recently defeated opponent, but it felt pretty organic in that it makes sense to celebrate a glorious victory with a feast even if it wasn't strategically the best move.
Feasts would go a long way to solving a lot of Bannerlord's problems. I also look forward to the potential of what a Bannerlord feast could be like. I am hoping for more interactions and more socializing to do. Maybe we can challenge other lords to a board game and gain some small renown by besting them in front of the other lords.