I hate the exhaust port complaint. People say that the Empire should’ve just covered it up, but that defeats the purpose of an exhaust port! It’s established that the port is tiny and apparently only someone with extreme propensity for the force can even hit it. Also, the port wasn’t what destroyed the Death Star. It was a chain reaction explosion caused by a torpedo making it all the way down the port and into the center of the space station. It isn’t like the exhaust port was a self-destruct button.
The funny thing is that when Lucasfilm addresses this complain, they add even more improbable and implausible stuff on top of the original plausible but improbable stuff.