The distribution of points is capped by events/ways now.
Up to a certain point level, M&B quests are efficient. After that, it is over.
That is thanks to the political game.
When the lords no longer offer you quests, you should be enough well with them so they can trust you in political games.
Ask them how to raise the common rank in the kingdom. They will deliver a quest that is related to one of their rivals in the Kingdom. If accepted, then you will grow better with the quest giver lord and possibly made an enemy of this other lord. You also need to be controversy free as you will take side with one of the factions within the kingdom. You can check the existence of these factions when in military campaign, you cross path with a small group of lords not joining the main military campaign, prefering to lead their own war. So a loss of efficiency.
Another thing is when you accept a quest of this type, the requirement is to be free from controversy. This excludes you from solving quarrels in the Kingdom (generates controversy) and is conflictual with the position of Marshall. Each lord has his own view on how to lead a war and the multiple decisions taken as a marshall (attacking this castle instead of defending this lord's property, releasing this captured lord instead of keeping him in jail etc...) will gain you easily controversy.
As politics grow, it is generally impossible to get well with all the lords.
You might even lead one to be inducted from treason and stripped of its possessions etc...
The aim is to reduce the internal dissent by kicking out lords who are unsatisfied. Reversely, you can attract other factions' lords who would fit better in the Kingdom moult.
As you grow better and better with a lord, it is also possible to influence him into a course of actions. Check anytime what a lord is doing and what the reason for its action. You might help him to serve better the Kingdom. When the lord benefits from the suggested course of action, he grows more favourable to you. Suggesting him to raid a averagely wealthy hamlet or some other stuff...
On a side note, the Kingdom of Nords is one of the most stable kingdoms in my game. Usually, people are united behind their King. Dont know if it is a game feature but from within, you might be able to instill dissent.