Science fiction novelist John Scalzi lists some of the worst designs in the Star Wars universe:
Yes, I know, I want one too. But I tell you what: I want one with a hand guard. Otherwise every lightsaber battle would consist of sabers clashing and then their owners sliding as quickly as possible down the shaft to lop off their opponent’s fingers. You say: Lightsabers can slice through anything but another lightsaber, so what are you going to make a hand guard out of? I say: Dude, if you have the technology to make a lightsaber, you have the technology to make a light hand guard.
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An unshielded exhaust port leading directly to the central reactor? Really? And when you rebuild it, your solution to this problem is four paths into the central core so large that you can literally fly a spaceship through them? Brilliant. Note to the Emperor: Someone on your Death Star design staff is in the pay of Rebel forces. Oh, right, you can’t get the memo because someone threw you down a huge exposed shaft in your Death Star throne room.