@meddler do you remember what happened when Gragas could pre-detonate his Q?
I guess Lux's E is a bit different since there's a reason not to detonate immediately but these kinds of changes usually don't do that much good, especially when she was perfectly playable anyways.
should just keep buffing the passive if you insist tbh
Lux's E being comparatively worse to other things isn't as bad either since her ult is so powerful and so readily available; I assumed that her ult being up every minion wave late-game had a bigger trade-off in the E.

