New game modes.
1) Free Trader Mode – Start as a small trading frigate and work your way up in ranks for whatever factions you like, earning money to upgrade your current ship or buy a new, better, bigger one. Scores would be easily ranked much like the original game mode.
2) Conquest Mode - Features a large sector map, with each star in it controlled by the various factions. The map will be ever-changing, and you will help your selected faction win over the entire sector by beating the others. Various stars will provide bonuses (like extra scrap, free repair facility, store, etc) This will create a really tactical game as controlling some stars that are strategically important and holding them will win or lose you the game. This possibly could extend to controlling the entire faction's fleet (sending them to guard other stars, etc)
3) Last Stand Mode - Always love this game mode, whether firefight in halo, horde in GOW, etc. Its always fun and challenging. Pretty self explanatory. Waves of ships try to kill you. You are limited to repairs every few rounds and you get access to full store every 5th round.
Someone else mentioned multi-ship battles. A definite yes! Building your own small flotilla would be just as cool as squaring off against multiple ships too.