I think this problem of the villains having mental problems is mostly a Batman problem.I mean I dont think you can find articles like this about Superman, or X-Men...Your thread is titled complaint with modern comics yet you are criticizing the films and say you don't know much about the comic books? The title of your thread may need tweaking.
I recall comics getting dark and violent about thirty years ago, actually. This is not anything recent.
10 Batman Villains & The Real Life Mental Health Conditions They Represent
Funny enough that link agree that the Riddle represents autism.
It is so prevalent that there is not way this is accidental... it is almost as if the creators of batman designed each villain around an specific diagnosis.
That said, I have not seeing this problem with other comics... they have different approaches on character design... I guess.
This other link starts up with reminding us that Batman villains go to an asylum...
Batman's Rogues Gallery & Disorders
I mean, I can keep giving links... there are thousands of results on google...
batman villains and their mental disorders - Google Suche