Let's be honest. Continuity for comics is lol. Any major story arc or character development is likely to be retconned or simply ignored within 5, 2 or even a single year, regardless of whether or not it's DC or Marvel. Blue Energy Superman, Azareal Batman, Parallax Hal Jordan, Superior Spider-Man, James Rhodes Iron Man, Frank Castle Frankenstein etc.

My question to you comic book readers, no judgments, is simple.

Which of all these drastic character arcs do you wish had not been retconned or changed? Which major change to character continuity do you wish the publisher had run with?