Ok, but the Nightmare Force merely feeds on, and amplifies negative emotions, so I wouldn't call it a retcon, more of an explanation as to how her appearance changed.

Dear Princess Luna,

Where in Equestria was Rarity in "Lunar Eclipsed"?

Confusedly,

KRX.

She was originally in it, but her part got cut for time.

Still, I think Rarity belonged in this episode more than Pinkie Pie. For goodness' sake, she runs a boutique!

No, that's what the Nightmare force does. Luna wasn't feeling neglected and feared, she was feeling unappreciated, and the Nightmare force amplified her emotional distress. Luna went rogue because her unappreciation turned into jealousy towards Celestia.
She was feared by the world because she became Nightmare, not before it.

And yeah, Rarity did deserve to be in Luna Eclipsed, but she was just inconsequential to the story, where Pinkie was vital (Though, if One Bad Apple is any indicator, Rarity was the one who made Scootaloo's wolf costume).

I think we could have done without some of the Pinkie bits just to make time for Rarity to appear.

At the very least, we have this (linked due to the immense size of the image):

https://i.chzbgr.com/maxW500/5376914688/h00D691FD/

Has anyone here seen Dusk's Dawn? Wow...it was bad.

I'm curious now...What is Dusk's Dawn?

A fan animation...with bad writing, and bad animation...

What's it about?