But what about the possibility of shifting that role to the adventurer class?
Not very high. For a number of important balance reasons.
Ninja or spymaster, neither seem like likely jobs for a noble in a feudal society.
...You don't think nobles should be spymasters? It sounds like
exactly the kind of job they'd be great at.
It's not something you advertise to the world. On the contrary, to all outward appearances, you're just another courtier, talking, gossiping, drinking...but all the while, your "little birds" are out gathering you information, or spreading the right lies. After the party is over, you retire to your rooms, to find a pigeon on the windowsill with a message canister on its leg. You read the report, nod to yourself, pen a quick reply, and put it back in the message canister before sending the pigeon back on its way.
Three hours later, the docks are on fire.
