As someone who has played well before Lux's release, I can say safely that she is probably one of the most broken mage mid laners possible. She has strong harass/CC early game, she has a huge power spike mid game, and still a very viable threat late game. She is undoubtedly one of the safest picks with maybe one or two drawbacks. She doesn't suffer from mana issues, has both soft and hard CC to escape with, and is able to not only single target DPS but really bring that team damage that many champions lack overall. (Especially of the mage variety)
She isn't a "hidden beauty," because anyone that has been paying attention in the past two years realizes she is a threat, even when she isn't popular. Much like Jax, she lives outside the meta due to the usefulness of her kit. AP nerfed? Go support and utilize that ridiculous kit. AP buffs? Go mid and faceroll yourself to victory.
She will be nerfed soon, and I will laugh at players like you who think they are special for playing her. Lux is the basic bitch of CC champs.