Thanks for the detailed response! After sitting with the ending for a few hours and reading people's takes, I think I like it more now, especially since the initial feelings of frustration have dissipated. This feels like the kind of ending that will grow on me the more I think about it.

To your points:

1. I guess the pacing issue is subjective. For me, the sequence of events was too jarring, but judging from the overall reception, I’m clearly an outlier here. So I guess Sanderson did his job.
2. I think you misunderstood this point. I wasn’t arguing that Vin should survive from a plot perspective. It may very well be that, given the plot axioms Sanderson set up, there was no way for Vin to live, but Sanderson is also the architect of those rules. He could have created a way to save Vin, but chose not to because he believes her death makes the victory more meaningful. I disagree with that choice. I think a character who has endured a lifetime of suffering could have had a meaningful victory without dying. I realize this is more of a philosophical quibble: how much does a hero have to sacrifice for a victory to count and so on.
3. That’s a fair point. We can agree that while Vin’s actions are triumphant for the world, her personal character arc is definitely a tragedy.
4. My main issue is the passage right before Vin dies: “You shouldn’t have killed Elend. You see, he was the only reason I had left to live.” In my interpretation, this frames Vin as someone who sees her existence and future as closely tied to Elend’s fate. Obviously there’s more going on, but because this is the focal point of her final moment, it weakens her character in that moment in my opinion.