Yeah, I kinda felt that this season. Like they were burnt out from the first few and didn't know where to take the characters next, so they settled on sex. I'm not complaining about the sex in the slightest -- I do think they were a big cavalier about the drug use, given how dangerous that specific party drug can be -- but the sex was fine for me.
I feel like they could have done more with Nadia. Shown her having a life in New York or introduced a crazy American roommate for her to have problems with...or temptation. Like maybe the roommate is cute or just a friend taking her away from her old friends in a healthy but sad way for Guzman.
I did think Guzman was regressing a little too much as a character. I mean, his new girlfriend is the same bitch his old one was before both of them grew up a little. I didn't buy that he fell for her so much. Maybe if it were more of a trick.