Even Vince Gilligan doesn't consider that to be a spoiler. He said it was going to happen all the time while the show was airing.

Vince Gilligan said multiple times as the show was airing, even as early as season 1, that Walt would die in the end. Even years ago, he did not consider that a spoiler, but a foregone conclusion. The show is how he gets to that point.

If you watched Breaking Bad and got the impression it only cared about plot, you are the biggest idiot in the world.