The size of the compass makes it a little overpowering at the moment. I'm not sure if that would change as more elements get added to the map.
I'd like to see some landmarks. Cities, obviously, but also some markers for shipwrecks and/or battles, ruins, suspected pirate coves and the like, where the PCs can go and poke around for treasure and adventure. Some cryptic notations might also be fun--some numbers or directions that mean nothing alone, but might be useful when the PCs get hold of some additional information later on.