This is something I posted on another site:
One complaint I have that I haven't seen mentioned anywhere is the de-evolution of Felix’s character. In Season One, he was an individual character, with an interesting life that was separate from the Clone Club. But as time wore on, he became little more than just someone who’s basically a servant for the sestras. He helps them out, watches over Gracie and Helena, and does little more than panic whenever a crisis pops up. It was fun to watch him kick in that door in the finale, but that seemed to be the most interesting thing about him all season long. I love that he has a bond with Sarah and her sestras, but I really wish we’d see a little more of his own life again next season.
I also have to say, when we were introduced to Helena in Season One, I didn't like her. She was clearly mentally unstable and dangerous. But it's a testament to Tatiana Maslany's talent and good writing that she was able to flesh out Helena to make her more interesting and sympathetic. I was rooting for her this season to continue developing into a great character. I don't think she's there yet, but hopefully she'll continue to evolve next season.