I really hate the idea of canon being something that can't ever be changed or reexamined. Stories have to evolve, and sometimes that means writing over or around something that happened before. It's fine. But fandoms tend to be so anchored in the past that they take it as an insult to the material.

These fans would hate the Original Trilogy if it came out today. "We were clearly told that Vader KILLED Anakin! This breaks canon!"