Purpose: Give new players a bit of guidance.
But I like your last idea there. We could integrate existing limitations into the system this way. Tell people that if they reach X prestige, options A, B and C as well as a few others will open up.
How about triggered guidance, rather than having a quest for things like recruit a unit or fight some monsters for example:
**Your men havn't been paid in seven days**
Game - Your men need paying you should pay them, you can pay them through the orders screen, you can also set standing orders for your men to be paid every X days
**You pay your men**
Game - As a new noble your trustworthness needs to be proved, you have proved you are an honest man by paying your men this helps your prestige
