After the existing game gets fixed, I'd like to see either an expansion or really huge patch that adds more to sabers. An advanced mode of some sort that would add:
1. the double bladed saber, but done well, with a unique set of moves that would look bad@ss and would keep the second blade out of your body.
2. a way to use 2 lightsabers (again, with unique moves)
3. a whole load of new acrobatics and moves for the regular saber to make it the preferred choice, and ways to block.
4. a new scoring system(one that would reward you for using a variety of moves and penalize you for abusing moves)
5. some new models that would have unique fighting "schemes" simply to make their fighting look more realistic. ie, a yoda model that would do lots of spins and flips like in ep2, but wouldn't do any extra damage or incur any less damage, or a jango fett model that would have a jetpack instead of force jump, a flamethrower instead of lightning, a grappling line instead of pull, etc.
6. more force powers, or should I say more realistic force powers that complement the lightsaber well.
7. Maps from memorable duels in the movies and books, and ways for players to take certain roles in the duels(like 2 players representing obi-wan and qui-gon facing off against a player as darth maul)
And a few things that would be nice but will probably not be included in any official expansion or mod:
- New multiplayer modes like team co-op, where players could fight together against bot enemies in scenarios from the movies or single player game (Players could be jedi in the arena on geonosis and fight off the attacking army, for example, or square off against a troop of reborn).
- As someone mentioned before, drivable vehicles could add a lot to multiplay. And not just ways to drive them, but ways to run down people, crash them into things, and share vehicles(one person drive and one person control weapons).
Of course, many of these things will never be made, but you must admit they'd be pretty frickin cool.