How many major navies from that time are out there anyway?

I mena... sure if they decided to make more thay could even use any country and just make up ships on their own.

But seeing as they usually go for nations that had some actual navy with at least several battleships... i seriously can't think of any nation that could fit the bill.

Maybe Brasil would fit partially but... meh.
I think SDE is done witn making nations. 

No this game is done with the new nations since the landscape sprites is filled to.

They gonna focus more on NF2 atm since its just an beta currently.

And what do you think? 

All of our sailors and credits will transfer to Navy Field 2, or we have to reset the game from the beginning?

You'll be back to square one. Count on it.

Italy is the final nation and nothing will be transferred to NF2..

And why would you even want more at this point?

Not until the rest of the ships are fixed.

And to be honest, I don't think there would be enough variation to do new nations. They would have to be huge extreme's, which are rarely good for the game.