I would like a MMO (Massively Multiplayer Online) game based on WWII with two factions (Axis and Allies) and with accurate simulation of the war and it's machinery. Let the video game players/simulation junkies duke it out all over again.
We could turn Flotillas into "guilds" (like the ones in existing MMOs like World of Warcraft, etc.). Man your boats with players (or AI characters), get upgrades and promotions for the reknown (or experience) and have fun.
Although I'm sure the devs, always having favoritisms, will imbalance and ruin it (like the class imbalance in WoW).