The Lux buff is overrated

This is like when people wigged out over Jinx's minor ult buff (yes, it was minor).

Seriously, it's not a big deal. Lux only gets the CD refund for actually killing someone with her ult, and it's negligible until she maxes out either her ult or her CDR. Now, once she has one or both of those, the refund is pretty nice - bringing her ult CD as low as 15s, potentially allowing two uses per teamfight. Sounds broken, except Lux can't always secure kills with her ult specifically, and doesn't always want to; lining up a huge AoE attack on half of the enemy team is often more valuable than singling out a killable target. Notice how this lines up with Lux's changing role over the course of a game; early and midgame, using her ult for picks is supreme, but in late game teamfighting, she needs to maximize her damage.

Essentially, this buff gives Lux more decisions to make. Do I ult to clear the wave or save it for a pick? Do I follow up on Malphite's engage and hit three Champions, or wait until one of their carries tries to run for it? Do I ult that Champion we engaged on to secure the kill, or save it until I have a chance to do more damage?

True, Lux didn't need a buff, but Riot managed to add just a little power and a lot of depth to her straightforward kit with just one mechanic - well worth any follow-up tuning that might become necessary. This is how Champions stay relevant and interesting in an evolving game like League. Honestly, this is the kind of buff more Champions need.