Sooo a lot of champs like janna get once in a while some mini reworks, while some champs remains untouched.
Lux is really annoying on every lane she can play , not only because of her high amount of damage, but also her cc and her instant e poke , that you can't escape.
My idea is as following: Why not put a cooldown of like 1 sec duration between the first and second cast, maybe increasing the damage for what easier farming, but making it so , that you have to play it strategic.
Playing as support and casting your E behind the enemys, making sure they cant escape, once in it and cooldowns off, recast,
Playing midlane, seeing your jungler ganking, throwing it behind your enemy, damaging him and finally blow him up in your E, while he has nowhere to go
Make your E more of a tool , for example the janna rework(new tornadoes), than instant poke.
Maybe makes laning a little more easier and tactic. (also without her making a mistake, and still oneshotting you)