I'm not concerned about nicotine either. I'm far more concerned about all the other stuff that comes with it, particularly the flavorings, but I suspect that coating one's lungs in VG all day long might not be the greatest thing in the world either. Hence I stick to MTl tootle-puffing my small-chambered, bottom-fed RDAs using 65% VG, 15mg/ml, at 15-20 watts, and I do quite enjoy it.
Bottom line: If someone IS concerned about nic, they should not be looking simply at the mg/ml level of their juice, but the total amount of nic they're vaping per day. Getting better gear and vaping lower nic juice may not cut one's total nic consumption at all.