My own take is that this is a misguided idea. Cigarette smokers are addicted to nicotine, not to smoking, and the fundamental harm comes from the smoking itself not from the nicotine. The history of low-nicotine cigarettes is that smokers puff more vigorously to get their normal fix.
So from my perspective e-cigarettes make much more sense - deliver the nicotine without the more harmful aspects of smoking.
Peter,
The counter-argument is that the real harm from smoking comes not from the nicotine, but from the tar. XXII also has a high-nicotine cigarette, the argument being that if the nicotine high is satisfied with one cigarette, then the amount of tar going into the system will be reduced, because one will be smoking less.
I'm not sure that your notion that "Cigarette smokers are addicted to nicotine, not to smoking" isn't too narrow and shows a strong bias toward a psychopharmacological model. There are questions of oral fixations here, not to mention certain kinds of peer pressure. I wouldn't be so quick to reduce the whole phenomenon to one of "nicotine addiction."