I also sort of blame the episode. It was just sort of there.
Luna's dream manipulation -- meaning, manipulation of a pony that she did in a dream -- is pretty well planned. Just like Fluttershy demonstrated when taming Discord, and outright explained to Seabreeze, the key is to start out nice so that people think of you as their friend, and *then* tighten the screws. An important lesson for all the kids!
Oh my god, Sweetie Belle is so evil. Every fanfic with an evil Sweetie Belle is canon now. She's upset and can't sleep, so she ruins her sister's life, and then sleeps the sleep of the just.
But really, the episode was just kind of... there. It wasn't bad but it was missing something.
I think I'll rate it 'not applicable'/3. Or maybe 2/3. It wasn't bad enough for a 1.