This is interesting and as much as I would like Starlight to stay a villain, I want to see how this turns out. She works as a villain because she's different. She doesn't operate like the typical villains we've seen in the show's season premiers and finales and her motives are still unclear (yeah, there's the equality ideology but it still somehow feels incomplete) and there is still more to explore about her reasons for wanting everyone to be equal. There's still the season finale to look forward to and I am hoping it will give Starlight's character more substance.
My only concern about this is that I don't know whether or not this will become canon simply because I don't think the books are canon to the show. I mean, sure, the Pie family's names were first mentioned in one of G.M. Berrow's chapter books and it was later adapted to into the recent Hearthswarming episode but beyond that, nothing else from the books show up. Then again, that trend may change given this book's release date is still in 2016 or maybe this is book will serve as a followup to the finale. Either way, I'll wait till this episode is aired before I give my thoughts about it. Don't want to give myself some expectations or hype and then be disappointed in the end.