SpoilerFun fact: Stevenson has talked about how that scene was designed to feel at least somewhat false. Shadow Weaver was a horrible person, she got in everyone's way, and her abuse of the children under her care defined her. Even her sacrifice was a manipulation: that's why she says "you're welcome" and gives them a smug smile instead of, I dunno, actually apologizing sincerely for any of her numerous abuses. She gets to make them "owe" her one last time, and then peace out instead of working to heal the damage she did. It's not a redemptive sacrifice -- it's a mic drop.
Agreed. The dynamic worked for me by the end, even if I'd also have loved more scenes of Catra atoning/apologizing to the rest of the heroes for her prior behavior. But aside from that, the concept worked for me. I think if Catra had died when she "wanted" to (after sending Glimmer away right before Save The Cat), her character arc would've been cemented by that redemptive sacrifice. I'm pretty sure she gets several lines about "I've been so terrible, I'm sorry, just let me do this one thing for you guys" in that episode. If she had died there, after a genuine self-sacrifice to try fixing what she had done, I think the viewers who found her unsympathetic would be an even smaller minority. But interestingly, because she fails to die after her heroic sacrifice, there's a little bit less goodwill from that section of the audience, seemingly because she gets off scot-free.
I don't feel that way - I think the narrative made her work hard for that redemption. In fact, I deeply appreciate how much effort the story spent after that point to justify Catra's affection for Adora and vice versa; they didn't just go "well Catra tried to Do A Sacrifice so now everything's okay!", they actually kept building on the dynamic. I would've loved more of that, sure, but it's already a far sight more developed than most arcs of its kind.
I couldn't disagree more with the "Spike" characterization/theory someone voiced above. Catra's arc is extremely clear from the get-go: just look at how she behaves around Adora in the very first episode. This is absolutely not just "some cool bad guy we redeemed because the fans liked them." Catra's story is there from the start. And it's the most emotionally compelling thing about the entire show for me.
She-Ra is an absolute gem for how it picks apart parent-child dynamics. One of my favorite aspects of the show; there's always something more for me to uncover on a rewatch.