I just recently watched the entirety of Crash Course World History, which is an excellent overview of the cool aspects of world history that your high school teacher forgot to tell you about. Most interesting to me were the episodes on Zheng He (the Chinese Muslim eunuch admiral of the largest fleet of treasure ships the world had ever seen) and the preceding episode on the Indian Ocean trade networks that Zheng He navigated.
These networks were a long-standing series of sailing routes extending from the east coast of Africa all the way to China, and it was all so well-timed according to the monsoon cycle that you could plan departures and arrivals with an accuracy of a day or two. Zheng He sailed these routes over the course of seven voyages to establish trade agreements with the major trading centers of the era.
This of course makes me wonder why there are dozens of Mediterranean seafaring themed games but relatively few (if any) concerning the "Monsoon Market." You've got a clear mechanistic phenomenon in the monsoon market, a cool central historical figure, awesome international culture mashups, trading and economic systems for gamers to tinker with, and a relatively family-friendly non-combat theme.
Right, get on that! I imagine a kind of Seasons rondel mechanic. A cyclical pattern in which certain goods are more valuable than others. However, the monsoon makes things interesting in that it cleanly breaks up each unit of game time. Perhaps it's a kind of pick-up-and-deliver game, with variable market values and a time limit? Hm!
Okay, I couldn't shake this idea out without thinking of a simple mechanic. Here's a really abstract way you could represent a cycle of trading ships, just off the top of my head.
Each player is dealt a random supply of resource cards. Half goes into their Storage (their public tableau), the other set into their Ship. A ship is a special card noting that this hand "belongs" to a specific player. The other cards in the hand are that ship's cargo.
Each turn, the players pass their ship to the player on their left, and each player must exchange one resource card in their tableau for a resource card on the ship.
When ships return to their players, players score based on set collection or some other method. The goal being to have your ship come back with a better cargo than when it left.
That's pretty abstract, so we could add some historical inspiration to make things a little more spicy.
For example, whole city-states were founded along the trading routes that otherwise didn't have any business being a major metropolis. (Srivijaya is pointed out in the video as one example.) So, make each player represent one city in the Monsoon Market, each starting with a predetermined unique mix of goods in Storage and a unique point value for other goods. The Swahili coast has lots of raw materials, but they want more precious Chinese crafts, for example.
Taking more inspiration from the nautical theme, I'd probably do research on how ships were constructed. Thus, you could also buy upgrades to your city or your ship with a certain mixture of resources. Cloth and wood for ships. Gold and precious gems for fine jewelry, and so on.
And despite the overall peace and safety of those shipping lanes, pirates were still a nuisance. So, between turns, maybe a pirate attacks a random ship, costing it one or more resource cards. There could also be land-based empires who want to be paid resource cards from your Storage.