Every 50 mastery=50 big ship weight (same effect as the parrot pet giving ship weight)
So, 1k mastery would give 1k weight, max mastery 2k weight. Would help offset the added weight of sailors, particularly for those who prefer using (or only have) the "combat" ships to barter with.
Another way of going about that, would be X amount of mastery negates 1 sailors weight, instead of adding big ship weight.
Could also add parley reduction cost with the higher your mastery is, in conjunction with the reduced parley cost with your lifeskill level. -0.5% every 50 mastery for example.
One huge annoyance for me that could have an easy QOL fix would be the margoria barter locations having their names added on the map icon of the ships while you have a compass in your inventory. So, the shipwrecked naval ship for exmple, would actually have that name labelled on it like any other node does on the world map. Currrently I have to have an out of game map pulled up on my laptop to see the location names, why make players like me have to use an out of game resource every time?