I'll start with the end first.
If you like the idea of trading in a pretty large scale, then this game probably fits your taste.
When it comes to the actual trading aspect of the game, it's pretty straight forward. Different towns have different produce and needs. You buy where it's cheap and sell where it's expensive. The more goods you buy of a particular type in a town, the more it rises in cost and vice versa. Later on it seems to get a bit more complex, you'll be able to establish trade routes and so on, but on the grand scale of all, it's simply buying and selling.
But there is so much more baked in. Maintaining reputation, new ships, crew, equipment, battling pirates and different factions, plundering, gathering influence in a town so you can start your own production, managing settlements, doing quests. I was incredibly surprised by the sheer massiveness of a game that seemed so simple.
My only "gripe" with this game is that the different ways you can lose is not emphasized enough. 4 hours in and I was almost completly wrecked. The game went from "this is to easy" to "is this the same game?!!" in such a small time window. Still, I'm looking forward to restarting as much as it takes to win (Shogun 2 player haha).