The other thing is the human characters--simpler styles tend to be easier to animate.  It's hard to tell from the land-exploration gif, but the animations seem a little lacking.  And, to be honest, the characters seem like they are not up to the quality of the environment, I think mostly because the artist is trying to draw the details rather than suggest them--the sprites seem a little cluttered.

Thanks for that feedback, I really appreciate it.  I'd be curious if you have any examples of character sprites that seem more appropriate for the environment.  There were definitely some design limitations since everything had to be customizable (clothes, hair, eyes, weapons).  These are some more examples of the characters and NPCs:

Art critique aside, god damn it I love it - reminds me of some old pirate game where you drove ships to Tortuga and such, boy what a punch of nostalgia...

One of the biggest gameplay inspirations was the old Uncharted Waters: New Horizons game for SNES.  Any chance that's the game you're thinking of?