It's not that the work's completely unnecessary. It's all justifiable (unlike one dentist I know of who was in the habit of doing expensive work on perfectly healthy teeth). It's just that he was a lot more gung-ho about grey area stuff than I'm happy with - I can't trust this guy to give me an honest risk-benefit appraisal.
As for wisdom teeth being yanked early on - that reflects a difference in attitude that was one of the reasons I went to an Australian dentist when I had the chance. US medical people, including dentists, are far more inclined to practice defensive medicine. I honestly don't know whether the surgeon was simply trying to drum up business on any excuse, or whether he was motivated by the belief that if he doesn't tackle any potential problems, I'll turn round and sue him if they turn into real problems later.
As far as I know, it's not normal practice in the UK (and I think Australia) to remove wisdom teeth unless they're actually causing a problem. My upper wisdom teeth came through normally, but were removed a few years later because they were decaying badly (I have a serious problem with not having much resistance to caries). The lower ones didn't erupt at all, so there were no problems associated with partly erupted teeth. It's only in the last couple of years that they've been causing trouble, and taking one out didn't actually solve the problem it was thought to be contributing to.
The Australian did also give me a second opinion on something else - white fillings. My British dentist was dead set against them a few years ago, with good reason - at the time they had a very poor lifespan compared with amalgam. They've improved in the last few years, but I still wasn't entirely happy about the current dentist's enthusiasm for them. Risk-benefit again - they're a lot better than amalgam for preventing seepage around the filling and subsequent decay under the filling (a major problem for me), but is the physical lifespan good enough that you won't be replacing the filling just as often anyway? Apparently they've improved drastically in the last couple of years, and they're almost as good as amalgam for expected life now.