Best Ponythread war yet
Anyways I think the timeline is that around a year has passed before Return of Harmony.
Now I'm not sure what you mean by oddly written. She was a legend that a holiday was based around. Luna misinterpreted the holiday as involving genuine fear of her. As for the change; it took time for her to recover from being zapped by the Elements of Harmony. That and being very shy initially due to just having tried to take over the world.
Finally are you working on your story idea? I am still waiting to give it a read.