Look, I understand that iconic characters and stories are subject to more limitations that lesser known characters and stories, but I don't think that is necessarily a valid foundation for film criticism. A film and its characters should be judged on its merits. That isn't to say that a film cannot fail because it messed with the wrong iconic elements or poorly handled their deconstruction, but a knee jerk rejection of a story because it failed to conform to a particular pop culture expectation doesn't seem like a good idea.
I think a good adaptation that experiments with iconic elements knows how push audiences and challenge them; a film like that uses the established expectation to enrich the story by testing the principle of that element. For example, Man of Steel and the DCEU have completely rejected any element of the iconic triangle-for-two. The DCEU's Lois never knew the bespectacled Clark Kent, and neither Lois nor Clark had to concern themselves with being caught between that dual identity. Lois was there before there was a Superman, and she never knew Superman without knowing he was Clark Kent. This is a deviation that seems to have worked for most people.
When it comes to values, I think as long as a story does not endorse a deviation from the core values, then that deviation is fair game. If Batman abandons his no kill code, for example, then all that matters is that the story treats this deviation as a deviation that cannot stand. A redemption arc, in other words, reinforces the core value. If Superman kills, then show why it is okay that he kills. In this case, show that he had to kill Zod or else an innocent family would have died. Make it clear that Superman could not see any other way, and that it broke his heart that there was no other way.
