I'm just now getting into the season, I found it hard to start because I didn't want to accept the Netflix titles were getting canceled. I have to say I love what they're doing with Billy, they somehow made him incredibly sympathetic. I don't mind the light scars since that's what he'd most likely look like after so much time given the injuries. I like how it's far more psychological, he can't stand to be reminded of the guilt he feels for what he can't remember. They took what could have been a gimmicky villain and turned him into an antagonist that's so much more interesting.
I also love how they're handling Frank. After the final scene of the last season I thought it was brilliant to show him deal his issues in a positive way and I was curious how they were going to portray him. I like how he seems to have gotten past the death of his family to the point where Russo's escape doesn't seem to bother him on a personal level. I'm certain that will change but it's nice to see the character not use his past as a crutch or and excuse.
Also, yeah the doctor thing is incredibly stupid but I file that under "If everyone acted reasonable the story would be over"