It would be great if there was no second death star at all. Ackbar says "for the first time, we have prior knowledge of the emperor's location". (he's like Sadaam Hussein, never sleeps in the same place two nights in a row). "We're going to the heart of the empire, to this particular tower, and we're gonna kill him. The Endor shield protects Coruscant (instead of death star), we have to take it out." Of course the Emperor is setting a trap, with himself as the bait. The throne room scene would need coruscant outside the windows, but if it's raining and nighttime, you don't need to see too much. When Luke is watching outside the windows, instead of seeing the battle, he's seeing hordes of tie fighters roll off an assembly line to meet the fleet. It's pretty impossible to do now, but someday...