What a twist! Did we not see this surprise twist character last season? Assuming we didn't, it seems logical all things considered, if perhaps a bit of a cheap trick. I like how we found out who Dr. Karl is and that he's a comics character (perhaps a bit of a deep cut). I looked it up and Dr. Karl Malus is listed as a "non-exclusive Jessica Drew character" in the agreement with Sony. This means that it was always fair game to use the character, although Sony can use him too.
I'm torn on Trish's story. I'm fine with her being obsessed (in the comics, she had this weird obsession with being a superhero), but the self-destructive drug use aspect isn't what I was expecting. I was expecting more of an action junky type thing. On the other hand, pairing her with Malcolm creates an interesting contrast since he's a former addict. Still, I like Malcolm, which makes it such a bummer that the foundation here is so fragile.
Four and a Half Stars.
The other option was a completely original character who was not at all a comics character. Considering there's very little resemblance in her story anyway, it's not like it's far removed from an original character.