Lux E idea

What if it starts out smaller, like her Q (maybe not that small, more like 's sleepy trouble bubble size), but then expands to normal size upon first enemy hit? Stays "normal" size if hits nothing and still zones until detonated or expires. Easier to dodge (more counterplay), but also helps Lux players not to overshoot their target?

By smaller size I mean like the size of Ziggs Q, Syndra Q, Xerath/Morg Q width...