I put these ideas under the Imperial Declines Commentary but I'll put them here, because they seem to fit here better than under the Imperial Declines. I feel that Bannerlord would greatly improve from adding these features.
1st- Hierarchal Feudal System- instead of Having just the King and his lords, there should be a hierarchy of lordship, as they had in the real medieval ages. For an example, there is the King, under him are say the dukes who owe the king direct fealty, and under the dukes are counts who owe the dukes fealty, therefore indirectly owing it to the King.
2nd- Feudal Taxation- In warband you only received income from your personnel fiefs, but Bannerlord should have a system in which the King could set tax rates for his vassals, and if the Hierarchal system is put into place then lords for their vassals. If the King raises taxes/tariffs (or what have you) then he will accumulate more money from his lords, but the lords will like him less, trade will decline over time and the lords will be weaker. The amount you can raise the feudal taxes to should be based on the stability of said realm. Feudal taxes existed in some real medieval kingdoms (Byzantine Empire, Holy Rome, etc) but some were to unstable or unwilling to put them in place.
3rd- Stability modifier- M&B Bannerlord would benefit from having a stability modifier in the game. Stability can be measured by: number of looted villages (More looted= less stability), wars, opinion of the king and his lords, number of bandit hideouts cleared (more cleared= more stability and less bandits) and so forth. Stability can effect the following: Tax efficiency, trade, number of bandits (less stability= more bandits), number of defecting lords and things along those lines.
Thank you, I have high hopes for this game.