It sure is, by some small portion of the industry. I don't think we'll be seeing any big EthyLox (if you'll excuse the neologism) boosters taking off as first stages, though: it's a complicated thing to deal with, Ethylene. it being a room temperature gas means it entails all the hassle methane or hydrogen brings (i.e. you need to chill it down in order to put it in a tank, build pretty good insulation around your tanks, deal with boiloff, etcetera) and since methane has one fewer carbon I'd expect it to get better ISP. What Ethylene is being considered for, however, is as half of a storable bipropellant system: Ethylene self-pressurizes at normal temperatures, so for pressure-fed engines and RCS it's pretty good, and it's supposed to burn nicely when combined with various oxides of nitrogen, which are also self-pressurizing: The combination doesn't get amazing performance, but if proven to work it would be much easier -and cheaper- to handle than the various nasties currently used for reaction control, stationkeeping, auxiliary power units, orbital maneouvering systems and the like: all in all the mixture seems to have the advantage of being a safe (well, about as safe as rocket fuel gets, anyway), storable, and highly energetic bipropellant: and you can use the oxidizer as a monoprop as well. I think it has a decent chance of competing with stuff like hydrazine.
there's a NASA paper on this https://tfaws.nasa.gov/TFAWS06/Proceedings/Aerothermal-Propulsion/Papers/TFAWS06-1026_Paper_Herdy.pdf
I suppose the system has the added benefit that you could use a bit of your fuel for ripening bananas?