Just my

.
I doubt Big Tobacco wants it banned, they probably just want it regulated as severely as possible so that they are the only companies who can afford to comply with those regulations, thereby owning the market with their junk products that will turn people off to vaping and force them to buy cigarettes again.
Big Pharma would benefit from it being banned because, for every person who wants to quit smoking and transitions to vaping instead of buying NRTs, fewer nicotine patches, packets of nicotine gum and prescription pills will be sold.
Anti-Smoking organizations want it banned because (a) it looks like smoking, and (b) it encourages kids to transition to smoking tobacco (which is utter garbage, since I have yet to meet anyone who tried a quality vaping setup and and decided that cigarettes tasted better). Also, if smoking rates start dropping due to e-cig use that means their funding will decrease.
The medical and health insurance companies don't have any interest in supporting e-cigs because they make more money when more people are sick and need chemo treatments, surgeries, etc.
Local, state, and federal goverments can't support e-cigs because that would mean less tax dollars coming in from tobacco sales. Unless they can tax the hell out of it like they do with tobacco don't expect any government bean counters to support it.
The only people who support vaping are vapers themselves, vapers' family members, and medical professionals who don't make any money from the aforementioned industries. That's why supporting the work of organizations like
CASAA is vitally important.