DarthPlagueis said:...most of what Lucas came up with was really an afterthought (Luke and Leia - brother and sister; Vader as Luke's father, then as Leia's father too...) it's not much of a surprise that some things just don't make... sense.
That's really the heart of all the problems with the plot holes and continuity errors. Lucas didn't have a master plan\story back in the 70s, he wasn't a terribly gifted writer, and he just made up stuff on the fly whenever he reached an impasse. It's no wonder the story makes no sense, no matter how many times he tries to fix it or explain it.
After Empire, it's just poorly written. In fact, there is a Lucas interview posted on here somewhere where he mentions writing in the Yoda line "no, there is another" because he was stuck, didn't know what else to do, and figured he's just think up something later when they were filming the next one. He was already in trouble on the second film. There was no master story.
To me, what seems sad & humorous at the same time are all the TFN gushers and apologists going over plot details and minutia trying desperately to make sense of all the plot holes & inconsistencies - while thinking they can reconcile the six films into a solid, continuous story. Even more hilarious is when they have to redo their work every few years after Lucas makes yet another change to the story.
They give him much more credit as a gifted writer & story teller than he deserves. What seems lost on them is the fact that if the story's creator can't make sense of the story, then there's no way they can.