I wholeheartedly agree with this. What you have already given us in combat, is so unique. One has only to look at the latest greatest pirate fantasy game, Skull and Bones, to see that Game-Labs have vision.
Naval Action has been around for a few years now, is ostensibly produced on an inferior engine, and yet it still has a startling, engrossing, realistic, Fourth of July, bombastic feeling to the gameplay.
Keep close to your vision. Your love of history. Be stubborn about this.
My only suggestions are to make the GUI as beautiful as the graphics of the game. Take your inspiration from paintings of the period, from vintage manuscripts. Don't look to other games for your inspiration, look to your vision. Look to history.
I can't wait to see what you come up with.