[Gandalf Parker]

The Early Era of a nation like Oceania would tend to be more water oriented than it would be later in its history. Getting onto land is an effort. On the other hand, undoing its limitations would probably be too powerful considering the advantage of taking all the water provinces as a strong base.

I wouldnt consider Oceania was able to "get onto land". More of a nation capable of getting a foothold on land. Then you have to hold it and expand on it using the land resources. Generally Id tend to try that early on when you can do it against independents rather than other nations.

On the other hand, later in the game you might have to shift focus. You do have advantages in the water. Structures, PD, etc. You might need to shift to a defensive strategy to hold the waters while working on alternate methods of escape (such as research).