@Wuvit Mm, yes you're right. Realistically, any such idea would really have to slot nicely into the voyage system. Which isn't beyond reason.. If you meet certain gameplay or account conditions (ships sunk since your ship last destroyed or number of quests completed in 30 days or account lifetime, etc.), you have the option of opening up a new track/theme of quests (bounty hunter, privateer, etc.) at the cost of some of your previous quest options (treasure hunting, wanton destruction/pillaging - not that anyone can do this now).
Certainly not quite as ambitious as I'd like to see, but perhaps more likely to be implemented. I had similar feasibility debates in Project Spark (RIP). In a sandbox game with open development by a small team, you always have more ideas than you can implement. That's really tough.