One topic that always surprises me is that which arises about, say "Ericksonian hypnosis." People who pose the questions about it don’t understand an essential aspect of Erickson’s contribution. (You didn’t actually make this error yet). Let me make an analogy to martial arts to make my point. I study Aikido. Many of the "pins," "throws," fist and sword techniques of Aikido are found in a dozen other martial arts: jujitsu, karate, hopkido, kendo, etc. The techniques do not really distinguish Aikido from other martial arts. But it is perhaps profoundly different from all others. What is it then that sets it apart? It is the philosophy - the idea on how, when, and why to do this or that technique. It is the relationship between people, as learned and practices, that makes it different - and noticeably so! You can say the same for Erickson's approach. Hypnosis is hypnosis. Suggestion is suggestion. Paradoxical is -- etc. There is research on these interventions. But Erickson's application depended on his view of people and problems. You can find research on positive regard, yes, and that sort of thing is in the ball park. But there is quite a difficulty doing more than single case study designs when you have to try to quantify and measure the attitude, philosophy, and approach to viewing people, problems, change, and the therapist.
So, that's the dilemma you researchers. Perhaps you will be the one to get a good bead on it. It will be like discovering that there is no research that, say, the Western world view is more useful than the Asian world view, etc.
Hope that helps put the matter in some perspective. Good luck on your degree.