Lux needs a buff. A very good one.

You dodge a Morgana Q. She'll just shield herself and run away.

You dodge an Ahri charm. She can ult away.

You dodge a Lee Sin Q. He can ward hop away.

You dodge a Xerath E. He's probably 1200 range away from you so it doesn't matter.

You dodge a Leblanc E. She can distortion or double-distortion away.

You dodge a Lux Q. For the next 15 seconds you get close to her and pound her face in because there is NO way for her to get away other than flash. She can't fight you close range because of relatively low damage and is all skillshots. That E slow is pathetic and the W shield wouldn't make up for the fact that you have the second lowest base HP in the game. Basically, you miss Q, you die, end of story. She's so vulnerable after missing her Q that you might as well just say the best Lux counter is a champion that knows how to sidestep well.

Heck, I wouldn't even consider Lux a long-ranged champion. Most of her damage comes from proc-ing her passive at AA range. Meanwhile Xerath can stay 1400 range away, fire mini-lasers, and have no need to autoattack unless he's OOM.

She needs a serious buff of some sort to make her less risky. At the moment there is NO reason to pick Lux over Ahri. Both have similar playstyles, except Ahri has significantly more mobility and is much more forgiving. I say, give Lux a speed boost of some sort when she casts W.