While I'd like a map aboard the Tantive IV, sort of a reverse GC's ISD Judicator, the other two I don't really like. Games like the Rogue Squadron series have taught me that when you have to make up new situations, such as hordes of Tusken raiders assaulting the stormies as they make for the escape pods, to shoehorn a movie situation into a game... then the idea isn't very good game material to begin with.

As for the branching storyline idea, I feel it has a lot of potential. You could have a three-mission campaign where you are to attack a fortress with a force dropping in from space, and load a map where you are to hold it against counteroffensives if the attacker wins and a map where you are to act as a rear guard holding the landing zones until your forces are ready to retreat if the attacker loses. A third map could be set in space, either defending the retreating forces or defending a convoy carrying supplies and reinforcements for the captured forces. And so on.

Or something like that. The 'Front lines' idea above is good, too. You could have a long campaign where the forces fight their way towards the enemy base, trying to hold onto the offensive and eventually capture the enemy stronghold.