So, the setup is really dead simple: a historical rpg, set in the South China Sea in the 16th century. To render that in gamer math: PIRATES+KUNG FU=WIN.
Think about it. Pirate ships are already a fantastic setup for an RPG group, as they allow players to bring in characters with a diversity of origins and skill sets and have their cooperation (perhaps tenuous and self-centered at first) make sense, as there is a very easy default motive: profit. This concept has already been explored with a plethora of games set up to take advantage of the "traditional" pirate venues of the Caribbean and other Atlantic waterways.
But the E/SE Asian setting has a number of advantages over that. First of all, I think the right players that are willing to learn some history to write character background will appreciate the novelty of something a little different than the ol' skull and crossbones. Second, there are a plethora of options for both players and GMs: Europeans are arriving, the political structures in several of the major nations (China, Japan, etc.) are in turmoil and allowing pirates more free reign, and all of that means lots of fun things to do. Third, though neither players nor GMs may care, the truth is that it is MUCH easier to get rich in East Asia than the Caribbean. The West Indies trade, while eventually important, was never in the same league as the valuables pumping through the trade routes of the East. Fourth, though a little historic license may be necessary to accommodate players' favorite styles, as noted above it is not much of stretch for all of the PCs to practice or learn martial arts. And without bringing in Sci-Fi/Fantasy elements, I don't know how you get much more epic than that.