Lucian's Piercing Light's delay should decrease with level.
It's fine in the early-mid game. But once Lucian reaches the late game, piercing light actually becomes somewhat risky to use due to how fast champions become in the late game.
.35 seconds is plenty of time for someone to close the gap and put Lucian in a bad spot.
I think a good change would be for his .35 second delay to decrease on the same intervals that his passive increases. Like at 1/6/11/16, the delay would be .40/.30/.20/.10. (.40 seconds) for level 1 would make sense since he'll be getting some major late game power.