Well, the problem is that people are greedy little apes. If they replaced the die, they would have to print a million new Vader dice for all the guys claiming they got 'the wrong die' with their Vader. (Or any other good legendary) I, for one, understand the logic, it's very sad for those that get misprinted dice, but we're all a-holes at heart, and we shouldn't be trusted
simple solution: require people to mail FFG a misprinted die in order for them to replace it with a correct die. Problem solved! and it took me all of 30 seconds to think of it.
If you get the wrong die, FFG fixes it by giving you the right card (then you can use both that die and its card). If you get a misprinted die, FFG says "Hey! **** you."
I totally agree with this. I don't think people are cheating if they "RETURN" the defective die to FFG to get a replacement "CoRRECTED" version. It's just the the right thing to do IMO