I think part of the solution with the trade packs banking, is that people essentially camp the "turn in" NPC.
I'm not sure if this would be feasible but it would be nice if the profit splitting would smaller the closer you get to the turn in NPC, and larger the further away. What I mean is if you're in middle of the ocean, pirates get 80% profit and trader gets 20%, but if they camp the NPC pirates get only 20% and trader gets 80%. It would push people away from camping the NPC since it wouldn't be profitable toward trying to intercept traders in the middle of the ocean. I think it would create a much more interesting experience, than just banking near the NPC.
You'd end up with a more interesting action at sea, as this is where the profit is...and traders would have a chance to avoid or flee from pirates or at least making a decent profit if they make it close to their destination. In turn, this might encourage even more traders to attempt making trade routes, which would also make the sea much more interesting. I mean you could have ships with no packs trying to distract the prorates from the real prize.
I have no clue if that would actually work to be honest, but I feel it would work better than what exist now.