Mad Man

I've had this idea for a while, actually. It's a bit different to the normal shooters out on the market, where you've got you're guns and you're out on the battle field, just shooting people willy nilly. A large portion of this game would be spent out at sea. The idea behind the game is Pirates vs the East India Trading Company/Royal Navy. The character should be fully customizable (On what else should you spend your stolen money? Except for more weapons that is - and bigger ships.)
      The basic concept is that you become a pirate, and you have to find a crew to join (I'm thinking that perhaps the game logs into your system's clock, and depending on what day of the year it is there would be different crews to join, sometime none at all). At first it's unlikely that you'd start with more than a small schooner, but you can sail around to find ships to plunder and potentially steal. With this money you can go out and buy guns, swords and clothing, or if you have enough, ships.
      This game should probably have some fantasy elements, such as the Kraken, the Flying Dutchman, ect. if only to keep it interesting after a while. By the time you encounter these "bosses" you should have a big fleet of ships. This should take most of the attention off the main character for a while, and bring in a more RTS style theme to the game, where you use the touch screen to take control of your fleet from a birds eye view, trying to tackle the enemy, or flee as the case may be.
     Later on in the game you may possibly be caught by the Navy. I'm not sure if I want to introduce a sort of 'Game over' scene where you get hanged, but I'm definitely open for your crew to be caught and be hanged. Perhaps you'll be asked to become a privateer, and you'll be given the choice to work for the Navy. This would not be a bad choice, especially if you get a bigger ship, a bigger crew, and a bigger amount of loot.
     And how about online? Perhaps you and your friends could come together and fight along side each other, or fight against each other, battling over the treasure.