Stories involving a protagonist with seemingly otherworldly gifts tend to craft a narrative where the possibilities and potentials are limitless. While this form of storytelling is very good at garnishing attention, it’s mainly capitalizing on the mystery surrounding the main character. People tend to fill in those unknown personality traits by projecting themselves onto the character.
The problem arises when the Author attempts to choose a reality for their character to follow. No matter what reality you pick, the story will never live up to the quintessential version everyone has uniquely envisioned. The more we learn about the character, the less we feel a sense of awe and wonderment. This transforms something that once held so much promise into something that seems mundane. It’s not because the story is bad, it’s just that it could never live up to its own open-endedness.
The hacking, portrayed as fairly realistic, especially for people used to Hollywood craziness, and the fight (against financial institutions) pulled quite a lot of people.
Then, fairly suddenly, you get hit with a mental illness angle. A lot of people didn't ask for it, and don't really welcome it. It's not just a show about hacking now. It's a show about a very mentally ill man with a particular set of baggage trying to cope with it, while being part/the leader of a very notorious hack team.
So yeah, if you really like the first season, you might not like the second one much. At least so far.
I remember reading the foreword to Fight Club where the author stress that the "Fight" in Fight Club is not what the book is about. He even considered other types of clubs/themes to convey the ideas in the book.
So perhaps that's a way to look at it: Mr Robot is Hacker Club and hacking play the same role as fighting does in Fight Club.