Playing around in the editor I thought the island's maps that get generated would be nice if it was possible to have a capture objective.
So, generate say 5 islands. 2 islands have HQ spawns(which can also be captured, resulting in a sudden death event if u have no other islands flying your flag)
I have had a look at the entities in the events section of the editor and i see a spawner, it would be nice if there was an entity/trigger that could be used as a capture objective.
I see the game mode been played by 2 players or 2 teams. Start survival or with some basic stuff near the spawn, build a boat and go on a capture spree if playing in teams can go all out medium to big ships but players would have to build from scratch so an arm's race is implied.
Capture all islands to win, or in 2 player game set time and most islands flying your flag win.