OK. Yes, it looks like there's a 10% or so risk of muscle pain (not permanent damage) due to statins. And these guys
http://juku-pt.umin.jp/pharmacother/lancet2010.pdf estimate one additional case of diabetes per 255 patients per 4 years, vs. estimated 5.4 prevented "major coronary events (coronary heart disease death and non-fatal myocardial infarction)" in the same group over the same period of time.
I think it makes sense for high risk individuals to try statins and see if they cause muscle pain / fatigue issues for them personally. Even if 10% or more drop out due to side effect, there seems to be no permanent harm, and there's benefit for the remaining 90%.
Re: diabetes, it's not clear to me that it isn't simply human/lifestyle factor. Some percentage of all test subjects changes diet, takes up exercise or stops smoking during the study. The ones seeing 50% reduction in LDL due to statins are less likely to do either of those lifestyle changes than the ones taking placebo.