Complete agreement with the proposition that we tend to conflate 'darkness' with 'complexity,' which explains some significant portion of what's wrong with contemporary aesthetics. The example cited is good:
In the second season of “24”, the last one I bothered watching, there’s a wonderful illustrative example. There’s the conspiracy to blow up a nuclear bomb in Los Angeles, thwarted by bravery and pluck, and for a several episode sequence all evidence points to the plot being a joint effort by several Middle Eastern governments. Planes are in the air, ambassadors are recalled, the world is on the brink. And of course Jack Bauer discovers the key evidence that reveals that the cabal was actually within the American government itself. Complex? Well that isn’t a simple plot. Dark? Well there were nukes and people dying. But morally complex?
All the air went out of the show at the exact moment of that reveal because it turned a terrible moral question of how to respond to a horrific act of war (do you drop the bomb even though the plot failed? Invade three other countries?) into a simple question. Find the bad guys. Shoot them.
This also explains the shallowness of the comic book movie aesthetic: there are no real stakes because the good guy is never wrong, and never makes questionable decisions--in a real sense of questionable, not 'this might seem wrong but actually I have good reasons for it'--therefore can never generate any narrative frisson. The worst offender being Nolan's Batman--who takes the blame for the Joker's actions for no discernable reason, whose decision to compromise the privacy of everyone in Gotham registers as unobjectionable--but so on further down the line. "Is the Good Guy going to do The Right Thing?" is not a very interesting question; what makes the template supposedly work--all that tortured emotion in the origin story, the angst, etc--means nothing because it is overcome whenever the plot requires it to be. There are neither stakes nor consequences. The result is an aesthetic work that is darker than it needs to be, the relentlessly grim slogs that show up all the time.