I am not finished with the idea, i am thinking that if Ubisoft decides to make it, they will expand the ideas and story, and other stuff.
I have an idea for a game, that will probably be very good, it is basically Assassins Creed IV Black Flag (I don't think it should be an assassins creed game, more like a new game franchise) but online, you play as a pirate or work for a country and you can customize your character how you want (Face customization, tatoos and such), you will be able to own a fleet and make Crews and then people can join your crew, you can take big ships and make them your main ships or buy them, you can also get bounties on you and such, there will be NPC bounty hunters as well as player bounty hunters, the game will revolve around money and lvl, you can upgrade your crew, ship and fleet, if you take a fort or a town (You will need a crew) you will get income, and you can maximize that income by upgrading your crew, you can also upgrade the town and make it more livelier, giving you more money, and you can also make a town by yourself (You will need alot of money and resources) Naval combat will basically be the same as Black Flag, maybe upgraded or expanded, the map will need to be big though, i am also thinking that you can travel to many nations and oceans, you can go to Europe, The Carribeans and The North Atlantic Sea, there will be alot you can do, have i mensioned that you should be able to smuggle and do other stuff like assassinations or trades to earn money? You should also be able to recruit captains for your fleet and maybe also recruit crew for your main ship if you want to, you could pick npc's or players with the best stats to be your crew. I think that such a game would be phenomical.