Patches, you can't always expect to be able to relate perfectly to magical friggin' ponies. I don't think most people have to worry about their brother marrying an evil doppelganger. Or chaos incarnate ruining the world. Or their ruler's sister, who has been possessed by some unknown evil force coming to make the world night forever.
But that wasn't the point of those episodes. The actual situations don't matter, but the emotions related to them should be. It didn't matter that the episode was about marrying a doppleganger, the crux of the episode was dealing with someone you care about apparently shunning your feelings, and choosing between overlooking something bad to make someone feel better and calling them out on a problem while risking being shunned. It didn't matter that the episode was about chaos incarnate ruling the world, the point of the episode was to not get too caught up in negativity and let it rule your life. And it didn't matter that the episode was about an evil force making the world night forever, the point of the episode was learning to rely on other people's help.
What, exactly, was the lesson we were supposed to take away from this episode? Don't let the charge of "destiny" dictate your life; do what you know you're naturally good at, unless destiny tells you to be a princess, then fuck your natural talents, be a princess?
Twilight has been working very hard the entire series, but not towards the goal of being a princess. It's like if you worked all your life to become an astronaut, and you were then approached by the President and told, "Wow, you've worked really hard at all this science stuff, I'm going to appoint you as head of the Department of Science." While it's an honor and all, it's hard to be totally happy about it when it means you have to give up what you originally got into the field to do. And I do hope that S4 goes into that.