1: Diplomacy
Improves relations with everyone, which:
- Makes your vassals pay more taxes
- Makes them give more levy
- Helps Prevent factions
- Makes it more likely your allies will assist you
- Makes it easier to plot since people will like you more
- Makes you able to reject vassal requests without losing face
- Adds a few more options like asking your liege for stuff because he likes you more
2: Intrigue
- Adds to plot power. This should not be underestimated, since you can more easily murder and plot your way to power and out of trouble which is often much more useful then waging war.
- Protects you against the plots of others. This mean it will be harder for your liege to plot to revoke you and for your vassals to fabricate claims and so on and so forth.
3: Stewardship
- + demesne means more income, more direct vassals as a talent pool and hinders factions because your personal army is larger
- More income direct
- Who doesn't like cash? You can use it to help with everything from relations to more mercs to more subholdings and buildings.
4: Martial and learning
- ... What's the point of these again? The learning improvement seems moot since you could accomplish that with building cathedral schools and universities with the money you got from Diplomacy and stewardship. A shame too, martial should increase your levy and provide a small bonus to your entire army morale and Learning should maybe speed up culture/religious conversion and give a larger bonus to tech speed.
Overall, as a count and a duke I would suggest putting focus on Intrigue-Diplomacy-Stewardship in that order, for a king and up go Diplomacy-Intrigue-Stewardship. You don't really need a large demesne when you can make your vassals fall in love with you and marry your king's daughter and murder all his sons >
