After watching last nights episode, I still found myself wishing for Red John to return. I get that he is not coming back and that the show is going a different direction, and I don't want to just flame it. 

That being said, I came up with a theory I haven't seen anywhere else and thought I would post it just because: 

Michelle Vega is actually Miranda Martins, who Red John didn't actually kill. She looks similar enough and has at least some character development in the lie she told to go with Cho. 

I highly doubt that this theory is accurate but if I had to pick a way for the show to reintroduce the Red John/Blake Associate/Visualize arc, this would be a fascinating way to do it. 

Thanks!