Interesting, I seemed to have an abysmally low rate of skill increase with sabotage missions. But then I did notice a distinct lack of Assassin deaths. I'll have to try this.

Generals I've given up on trying to cultivate anything really. Dread/chivalry is somewhat controllable, Piety not at all. Ostensibly being born in a province with a Huge Cathedral, some Cardinals, and 100% catholic would probably make generals have some piety traits. Just speculation though. Crusading helps of course. But the god-damned Pagan Magician. Seriously, wtf.

Merchants...well the best thing to do really seems to be not to mess with Merchants too much until you have the guilds. Because the only way to raise Finance skill, other than extremely risky takeovers, is by leaving them on a resource for several turns. Which means early in the game, you can't have a high rank merchant before he's about 50 or so. When you start getting those strapping 22-year old MBA graduates then you can level them up on a resource, and have your 30-year old hostile takeover specialist wreak havoc.

A note about Merchants, and Diplomats. There is a nasty tendency for them to pick up "Quite Religious" or something similar, which does nothing but reduce their skill. It can negate the bonus of the guildhouse, which really sucks. I am not sure if it is religion itself, priests, or religious buildings that cause this, but after discovering this, I will be sure to minimize the infulence of the church in the cities that I want to produce merchants and diplomats.