Glad you liked it! By "world's were not invested in" I mean the "tales" that were the predominant narrative in 2 out of 3 of these, and the Pie's "traditional" rock farm, to a lesser extent. In new worlds with new characters, they have to build our investment from the ground up, for a one-time thing. It's hard for that to reach the same level as the top-tier episodes that utilize the characters we know we're following long-term. They always do something to tie it back to the main cast, as well as create a nice moral in general and some of their good trademark entertainment, but hardly enough for me to call them great episodes. (Or in Hearthbreaker's case, that slapdash Confalone storytelling just didn't do the greatest job geting us beind either the Pie's traditions or Applejack's attempts to improve them.)
With Starlight, I think they could've, say, made Sunburst the "sister Fan" and gone into detail about Snowfall's growing hatred for holidays and recreation, in ways last season didn't go into detail on Starlight's growing hatred for cutie marks and differences. They could've made it seem like both characters forgot how things like that allow for real emotional connections, and the story inspiring Starlight to want to try it would've felt more meaningful.
As for Starlight having more overly "heartless" goals, that kind of makes her more Scrooge-lite to me, not less. What people forget about Scrooge is that he's actually a pretty dimensional character, which is why the story works so well. He's over-the-top, but he's what someone really would look like if time, fate, and lifestyle made them that bitter, so seeing it all reversed really is a journey's worth. With Snowfall, they're kinda trying to get too much from too little, so it seems like a pale imitation.
Anyway, with my like/hate relationship with Sweetie Belle Toils, I'd probably have a tough time picking the episode I like better. Other than Pinkie Pie's scene, Toils probably had higher highs and lower lows. But yeah, when it comes to this episode, it looks like we liked it about the same. Oddly enough, this show seems to do just about EVERY holiday (so far) better than Christmas.