My only gripe about Cranial is that too little time is spent in the lab palpating. Dr. Stiles and Dr. Litman at PCSOM do a decent job of explaining the theory, but the students don't get enough time to really calm down (stressed getting ready for the practical) and feel the CRI and more importantly, sutural dysfunctions.
Also, there was one published study at MSU, I believe, claiming a 0.87 inter-rater reliability (nope, I don't have the reference handy, but can dig it up).
I have witnessed many folks getting relief from cranial from Fellows (some forms of headaches, sinus drainage, and one or two kids with chronic OM). I've received cranial a few times and couldn't tell much difference, but I didn't have major dysfunction.
I was able to pick up the CRI on the first day of lab, but then again, I've got pretty good palpatory skills (I picked up functional, etc) pretty quickly. I also really work at it (why just sit in lab with a bad attitude, wasting time, when you can at least TRY to learn new skills?). I've been able to help a couple of people already with simple torsions and side-bending dysfunctions, but am by no means an expert (note: I've not been to the Cranial Academy and I'm not a Fellow, just a better than average student).
As for needing additional evidence, I agree! We spend too much time as a profession worrying about whether our graduates do a rotating internship (with NO OMT!!!), than focusing on simple trials that will add to the literature about the efficacy of specific OMT vs. generalized therapeutic touch. That said, with our academic schedules as full as they are, who has time to do it? I think Sutherland, Fryeman, etc are on to something with cranial, but it has been poorly explained, by and large, and poorly demonstrated for a majority of students required to take it and regurgitate it on boards. The educators have to get to some sort of consensus with regard to OMT, standardize the way that it is taught, and then get it out to the students. Otherwise, we are a bunch of confused MD-wannabe's (stepping off of that soapbox now).
Give cranial another shot, if you can. If not, just learn the definitions for the boards, but realize that there may just be more to it than you are able to appreciate.