My favourite Star Wars game remains Star Wars: TIE Fighter, even to this day (the game is 16-17 years old). It was immersive, deep, and the mechanics were well balanced. Starfighters that were legitimately stronger in-universe required more hits to destroy (unlike arcade-style games like Rebel Assault or Rogue Squadron, where you could take dozens of hits, but each enemy required just one.)
But X-Wing, TIE Fighter, and X-Wing Alliance were limited by their time period. The prequels werent' out yet, and the EU only went about 20 years into the future. Also, all we knew of the ancient past was from the Tales of the Jedi comics; KOTOR was still years away.
My game would be a return to the gameplay of the X-Wing and TIE Fighter series.
The game would have multiple campaigns, which would each have about a dozen to fifteen missions. The game would come with 3-4 campaigns, and you could buy others later as expansions (like Starcraft II).
In one campaign, you might be a pilot for the Empire during its rise. You would fly late-model Clone Wars vehicles, like the ARC-170 and V-Wing, and later on fly new TIE Fighters and TIE Bombers (this would add an element of difficulty, as your starting ship is durable, but your later ships are not.) Your battles might involve customs or blockade enforcement, hunting pirates, stopping nascent rebel movements, etc.
In another campaign, you might fight for Revan, first as a Republic pilot fighting the Mandalorians (the middle mission might be Malachor V), but then start flying Sith fighters after Revan becomes Darth Revan.
Another campaign might be set during the Yuuzhan Vong War. You could be a pilot for the New Republic, defending against Yuuzhan Vong attacks. Maybe one mission might involve flying a stolen Coralskipper behind enemy lines.
My point is, there are numerous conflicts across the Star Wars universe, and numerous sides for each. There are dozens of possible campaigns one could have.
TIE Fighter had a pretty standard set of rules, and this game would match those. Your ship had forward and rear sensors, a targeting computer, controls for speed and power distribution (recharging your weapons, shields, or tractor beam meant cutting into engine power). Individual systems could be temporarily or permanently destroyed as you took damage. Ships also had short-range sensors; getting within 5-10 meters of a ship meant you "inspected" it, and the cargo appears in the targeting display (useful for missions where you're looking for Rebels or Pirates or Smugglers).
Weapons came in a few types: laser cannons, ion cannons, and warheads. All lasers and ion cannons were the same strength (though if you were running low on charge, a weakened bolt was fired). Laser cannons and ion cannons first took down shields, and then would affect either the hull (lasers) or systems (ion). If a ship's Systems got down to 0%, it would be disabled, and could be boarded by a transport ship. A disabled ship could only be revived if a transport or tug docked with it. Ships with warhead capability could only carry a set number, though some missions included a tug or Combat Utility Vehicle to refill your warhead load. Warhead speed and yield was constant to the model. Concussion missiles were fast, but weak, and useful for shielded starfighters and intercepting bombs. Proton torpedoes were slightly slower, but slightly stronger, useful for small capital ships and transports. Heavy bombs and heavy rockets were slow, but very powerful, perfect for capital ships and stations.
Capital ships and stations also had laser cannons, ion cannons, or warheads, operated by turrets across the hull. Those turrets could be destroyed. The strength of the laser or ion blast was identical to those of any fighter.
Starship speed while at sublight is important. The larger the ship, the slower it was.
Fighters without hyperdrives needed to be launched from and retrieved by a capital ship. Fighters with hyperdrives could arrive in a battle without support. Entering hyperspace ends the mission. The presence of an Interdictor meant no one could enter hyperspace (note that some missions required something like "Imperial Star Destroyer Glory must enter hyperspace", so destroying the Interdictor becomes key).
Each mission has primary, secondary, and bonus objectives. The primary objectives were given by an officer. The secondary objectives given by some strange figure, and might reflect the larger goals of any Order your character might be in (note that Maarek Stele, the character in TIE Fighter, was an Emperor's Hand). Bonus objectives are just fun, and you try and figure them out through the mission (example: if the objective is "50% of Freighters must survive", the bonus might be "100% must survive". Or, if you need to destroy containers or ships, the bonus might be to inspect them first.)
These games first appeared on the PC, if only because those had the best operating power at the time (and best controllers for the purpose of a flight simulator). But since all systems have analog sticks now, I can imagine using an XBox 360 or a PS3 to play this game. If it is on PC, it should be sold through Steam, thus facilitating the sale of Downloadable campaigns later on.