The idealization can be a part of therapy, but it does not have to be there to make it work. It depends on the particular person's patterns... Someone might never idealize the therapist... Everyone uses different defence mechansims, everyone experiences transference in different ways. If you used to idealize, but no longer do-- that could be a really significant step in your therapy, in which you are able to see your therapist as a real person-- you are able to see yourself and your therapist more on an equal level.