I think she was the cause of the dead world when Twilight pulled Starlight Glimmer with her.
That was the worst-paced episode of MLP I've ever seen. It dragged so much, the cold open was completely useless and the reason for Starlight Glimmer's corruption was mediocre.
I suspect Pop Fly is supposed to be a pegasus, and "pop" is a variety of music. It's kind of weak but what can you do?
It makes a lot more sense to make this a redemption episode for Spoiled Rich as a Scrooge character. Applejack's mom or dad would be the "Marley" character perhaps. Twilight would be Hearth's Warming Past, Celestia gets to play Present while Luna in Nightmare Moon mode is Future.
This never has been as far as I can tell. The only difference is whether it was influenced by Saturnalia (in the first millennium), Yul or other local Pagan traditions (up through 19th century or so) and the modern syncretic stuff. This is sort of like the people who pine for the "good old days" most of which weren't good at all.
It's the best Applejack episode by a (country?) mile. A problem episode with AJ which is neither the literal interview-weakness "sometimes I work too hard" ("Applebuck Season"), AJ is temporarily insane ("Somepony to Watch Over Me") nor a generic godawful Spike episode ("Spike At Your Service").
There is a bit of a disconnect between uses of the same term. In one sense, a "god(dess)" is a being that has immense power and desires others to worship them; the alicorns very explicitly do not meet this definition. The other meaning is simply a being of cosmic-scale innate power, and the alicorns DO meet that definition. After all, canonically, the combined power of four alicorns can fight the combined magic of all the other ponies in the world (plus Discord!) to a standstill.
It's also good for him/her to be an Earth Pony since the natives of the Empire are Earth Ponies too.
What's even worse is that the only parts of the episode that are even kind of OK are background things and visual effects -- storyboard and animation stuff. This displaces "The Mysterious Mare-Do-Well" as the worst debut episode for a writer in MLP.
WOW. I was already pleased that Diamond Tiara was going to be redeemed -- and in an episode that says that parents are not always right. But then the CMC get their marks. And inside the shields, they are three of the six Elements of Harmony (Although the bearers mostly had them in groups of three, the gems are all singular.)