Were it about the first half of the Fiendship comic, I’d be all about Radiant Hope trying to “Redeem” the Sombrero she knows and loves.
The second half, with the stupid “Mommy Red Crystal makes you instantly evil and lowers your IQ so that you go on a rampage instantly” twist just… doesn’t allow that. Sure, she might think that he can still be saved, that there’s still some good in him, but that’s because she doesn’t know the whole picture about the “shadow ponies” being ALWAYS evil. Ughh.
That, or we’ll end up with a cliched “Person that thinks they’re doing good performs atrocities without realizing they’re being self-righteous, does a full 180 degree turn conveniently at the end”. This is a 4-part arc, which also implies that only Cadance and God-Princess of Ponykind Twilight will do anything?
If this doesn’t work out, and let’s face it, it ain’t looking good so far, I believe it’ll be the end of the main series.