Hey Josiah, great to see you working on another piece!
I think Mouse hit the nail on the head really. I don't have quite such strong opinions on the border, but equally I don't think it'd hurt to have a little play around with it to maybe make it pop out a bit more in the darker parts of the sea. (I don't like how the country division crosses the border at the top though).
Font-wise, the smaller font works, but as Mouse says, that larger font is a bit too incongruous with the rest. A bit sci-fi maybe, or maybe something slightly Old Westy, but either way, I'd go for something different.
Love your choice of greeny palette, but it might be nice to throw in a few bursts of dark red in the symbols or font to balance things out a little. Whatever the case, I'm sure it'll look mighty fine at the end.
Anywho, overall it's looking pretty neat, just those few nitpicks. Look forwards to seeing more!