Well if LucasArts is indeed watching, then I suppose there's a slim chance of getting some ideas implimented. That being said, I figured we might want to suggest some.
My primary idea is the for changes made to campaigns (assuming it will have campaigns). I'd like to see open ended campaigns, where the story unfolds based on how you did on individual scenarios. Forget the you-lose-a-scenario-and-you-have-to-redo-it crap. If you lose, the next scenario is different than the one you would have reach if you'd won. Yes, I realize this is a lot of extra work in scenario design/story telling, but it also extends the replay value and allow for multiple campaign endings.
To that end, I'd also like to see Multi-player campaigns, whether they be co-op, pvp, or both. Again, the story will progress based on who won individual scenarios. And simply attempting to wipe out another person in pvp may not always win the campaign. In fact, it may cause a loss to the "victor" if their scenario goal contradicts slaughtering their opponent (say, if the needed to capture something but destroyed it instead). Co-op players may have individual or share objectives that they can help each other out with (one of which might be meeting up with each other)...