I think the E ability on Lux's visual update on the base skin doesn't have a "snappy" enough feel to it when it explodes, like the old one used to. It feels a bit flowery, like Neeko's blooming ability.
And Final Spark doesn't have the old warping effect after the spell fires, where there's like a heat-induced waveyness to the air surrounding the area the laser was fired in. I think the spell would be a lot better if it had these old effects.
Thanks for reading!