No worries, glad to see we can have a reasonable discussion about it, no mean feat over the internet!
Again I agree the NLP-esque, a-v-k styles have a contentious and debateable background, but personally I find a good old
Elman induction is fine and works great most of the time. For me, I'm not really fussed about which induction is better than which, its all a bit pointless as the bit that IS interesting is the effects you generate once they're in trance.
Look, as for the bit about whether its the placebo effect (which is simply a form of self hypnosis), expectation or whatever, its only important to understand the relative importance of all the parts if you're trying to modify it for some reason. Otherwise the fact of a person, a) has problem, b) goes to hypnotist and c) is cured, says all it needs to really.
re altered state, simply different activity to normal waking consciousness. Again you're focusing on tiny technicalities and missing the big picture of is the person actually cured/demonstrates the required effect?
As for "I am also not willing to accept that one person has the 'power' to stop somebody feeling pain during an operation" you're WAY behind the loop there, as hypnotic anaesthesia has been recorded in Egyptian times. Also check out
http://en.wikipedia.org/wiki/James_Esdaile. Dave Elman wrote a lot about him in his book Hypnotherapy, and also Dave's own work in the medical field again with hypnotic anaesthesia. He trained a lot of doctors to use his techniques and to this day is held in high regard.
As to why its not so much in common use in hospitals, its chemicals are simpler, more consistent and ability to give precise adjustments and quantities to those people who demand precise details

Despite the fact that it kills patients. So again slightly missing the point!
Hopefully I've given you enough to think and read about there
Oh and a final link for you
http://www.guardian.co.uk/science/2012/jul/22/hypnosis-revival-neuroscience-vaughan-bell