I believe that we are being led down a garden path with all this talk about Red John being a character we are already familiar with.

I believe that Red John has been exceptionally honest with us.

I believe it is a man whom we have yet to meet.  Reginald is his first name,  Surname is Onn.
He is known as Reg Onn,  therefore he told us his name, he has effectively hidden in plain sight...

But then again,  I'm not sure I know what I'm talking about at the best of times...