I don't feel that it is lazy story telling. It is not like they did the trench run again, it was a new design with new flaws, and the story around it was done completely different. Would it have made a difference to you if it had been a doomsday weapon with a different shape and name? As far as superlative weapons go, the Death Star is a pretty sweet one, what better way to end the trilogy.

I always hate these stories where the bad guys have a really good idea on their hands, then abandon it 100% just because the good guys luck one time and put an end to it. If I were in charge of the Empire I'd accept the loss with the first Death Star, and get at least to more into production immediately and throw whatever money necessary at keeping their construction quiet.

Using the Death Star as bait in ROTJ in order to draw the rebels out squash them was a pretty good plan actually.