I'd just like to see a requirement that all products have a label which lists every ingredient, even if that label is only available online or by mailing the manufacturer. And "natural and artificial flavors" is not an ingredient. "Meets the flammability requirements of the California Bureau of Home Furnishings" is also not an ingredient.
However, labeling doesn't really help people exposed to second-hand whatnot. The smoker/vaper(/perfume-wearer) may find the ingredients to be acceptable, but what about all the people around them? And unfortunately, smokers are not the most considerate bunch.
If every product had to disclose this, then ideally you could recursively query for every component chemical. At that point, not only would banning e-cigs be discussed but also probably many building materials and cleaning products. And we'd be able to ban on a granular level, e.g., any product emitting more than 10 ppm diacetyl.
I very much want to live in a world where the public debates issues from a position of knowledge, rather than positions of deliberate ignorance motivated by tribalistic passions. :(