Before I go, I'd like to note that this is just ideas and talk, I don't have the ability or time to make this game for real right now.
Obviously the first thing to do before designing a game is to decide what kind of game I want. Because I absolutely love space games, and there aren't nearly enough of them on the market, I'll design one of those.
The game, which I'm calling by the working name "Star Control Online" (cheesy, I know), will be an MMOG set in space. The setting determines the look and feel of the game.
I've decided on the following list of features that I hope to implement:
Modular Components for Ships
Player Owned Space Stations
A Sandbox Environment
These wanted features will help me determine how to go about designing the game, determining the mechanics and even the look of the game.
Newtonian physics means no traditional dogfights, no space friction, no up and down. This mimics the way things work in space in real life.
Seamless travel means that the game has no sectors, and a player can travel anywhere within a solar system. The only loading screens would occur during travel between solar systems. However, this means that SCO can't use just any engine, and requires an engine capable of procedural generation, which aren't that common. If one can't be found, then this feature might have to be discarded.
Indy games often have trouble making enough content to have a good variety of it. If SCO's ships are modular, then that means that there can be more variation in ships with fewer models. Two players can be flying the same ship, but each player can have their ship equipped for a different use, with this shown by the fact that their ships look a bit different.
Modular components for ships allows for greater customization and specialization.
Player owned space stations allow players and player groups to claim territory.
A sandbox environment allows players to set their own goals and create their own stories, as well as following the storyline of the game.
Open PvP means that very few areas of the game are truly safe. This drives player interactions if done right. The problem comes from balancing it so that it doesn't turn into an EVE style fragfest.
Now that I know what I want to do, I have to figure out HOW to do it. This is the kicker.