I am sure they will add the Santíssima Trinidad as a special ship, there was no other ship in this type, same as for victory so it should be this way.
There are interesting ships in the spanish navy of this time, the 112 gun ships like the Santa Ana Class for example.
Then they could/should add more of the american ships, the russian would also be fine.
Denmark and sweden will also be great to simulate the baltic see battles.
Also they can also expend the game with the Anglo Dutch war ships, the ships of this time will look different ( more galeon like with much more gold etc. ) but the game mechanic can be the same.
Here are some pictures from langton ships of this time made by "Model J" / Redcoat / Julián: (
http://modeljship.com/en/ )
Attachment 11003
Attachment 11004
I am awed every time i see how good his models are!
So there are much options for the future of the game.
But i think its
important they don't wait to long to add stuff so player move to another game when no addons came in descent time.