Ok, let's compare the movies with real life.
The Movies: Death Star is built, blown up by assholes. New one is built - same fate.
Real life examples of human stupidity!
The luxury liners of the 19th/20th century. They were huge, costly and eventually unecessary, and a lot of them sank. But they kept building more!
Twin Towers. Knocked down by REAL assholes, but look we're building more at great expense.
Jackass - totally redundant program where idiots do dumb things. That went on for a while didn't it?
Look, I actually find the redundant construction of 2 Death Stars one of the more convincing human elements in Star Wars. It's such a stupid, human thing to do! In fact I'm surprised there wasn't about ten of the damned things.
An edit of the films to remove one of the Death Stars would only exemplify the message of human stubborness displayed by the costly construction of those technological terrors, so fire away!