1992 vs 2010

[The Dark Knight]

"Dark" is more "in" today than it ever was.

I saw maybe one story that mentioned parents upset about the dark elements of Dark Knight. I believe Batman Returns had a lot more stories that contained negative references to its dark elements.

Although, in some respects, the Penguin is a darker character than Heath's Joker.

He is. A man/beast that lives in a sewer, spews black bile and wants to murder bubs doesn't compare. Dark is in, but not to this extent.

Even though people complain about the level of darkness, the "purity" aspect  is the biggest factor I think.

As I said earlier, the majority of Batman "purists" are not going to accept this take. No matter what era. Especially now, with the comic Penguin character built upon more than what it was back then.