Comic Book Adaptation: Betrayal and Fidelity

First things first, this post involves MAJOR SPOILERS for "Iron Man 3". This isn't a review of "Iron Man 3" mostly because I don't really think writing a review of "Iron Man 3" would be much fun. It was a rather good film, but it didn't fill me with an overabundance of glee or excitement as I left the theater, not necessarily because of any specific failings, but because it was altogether a rather nice, self-contained film without any major lingering plot threads or big questions that are meant to resonate.

But the reason I bring up "Iron Man 3" and the reason I'm going to spoil it big time is because there's a twist in the film regarding one of the characters that is a very substantial deviation from comic book canon, and it has a lot of comic book fans up in arms. Really, that's what I'm here to talk about today.

When is it OK for a movie or TV show based on a comic book to alter the source material and when is it unnecessary?

OK, here we go. SPOILER time.