The way I see it, the question is not so much whether it is appropriate to criticize the therapist, more whether doing so is helping you. Is it? If yes, then do it, by all means. But if listing all these flaws to your therapists, moving from one T to another, does not help you get better in your own life... then I really wonder what the point is for you, other than avoiding the things you might truly need to deal with? Spending a lot of energy and time on a a rather sterile endeavor?