Are you going to introduce some form of dynamic conflict. Playing each faction to 50 made me rather dissapointed in that once you get to Ilum, both sides in their own versions have 'beaten' the opposite faction and is just cleaning up. This theme covered every planet the factions share.
It's heroic and all but, once you play both factions there really is no weight. I don't get quests on Alderaan to take the 'Spear' turrets as imperial, while republic players get a quest to defend it from NPCs, despite the whole explanation that they are a important asset. Why not get some linking of these quests, rather than have everyone scurry about saving the world from the opposite faction on opposite ends of the map. Get the factions running into each other outside of Ilum (which really is just focused on one separate zone that is placed there to be 'contested').