Return of the Death Star

Yesterday we argued that the Death Star plot in Return of the Jedi was unnecessary. 

Harris countered, correctly in my view, that the Death Star was built to lure the rebels into a final battle.

The second Death Star seems contrived to us. There's nothing inherently wrong with that, we do it too.  We just think Lucas could have done better with a different idea. 

We also restate that we love Return of the Jedi and everything about the battle around the Death Star.

Still, Lucas didn't have to use the Death Star as a plot device. Why not have some grand imperial conference on Coruscant as the trap?

Also, and we don't want to take this point too far beacuse one can argue any movie to death this way, would they really have built a second Death Star after what happened to the first?