This is coming from someone who mains Lux on mid lane.
Seriously, this skill is absurdly strong.
The projectile speed is pretty fast, and the instant detonation leaves the enemy player no time to react, cause the projectile is already near them when they see that.
Also the detonation range is HUGE, like holy crap that's seriously large for everything else that it has.
The base numbers are also pretty huge, and the AP ratio makes it even worse.
Seriously, do something about this skill.