Lux > Viktor?
Viktor sees LCS plays yet it seems that Lux is just better.
Survivability/Self-Peel Viktor deals more damage late game (in theory) but cannot self-peel with W even a quarter as effectively as Lux with her Q. He's much more likely to be rapidly deleted in a team fight. It doesn't matter how HIGH Viktor's AP is on paper if he's just gonna get instal-bursted by an unfed Kha without any ability to defend himself in the late game. Lux's Q is way more reliable than Viktor's W defensively... I cannot tell you how many times people have simply Flashed or Dashed past Viktor's W to kill you anyways. Try that against Light Binding...
Lux's Ult > Viktor's Ult Viktor's Ult is clunky as hell to control, its short-ranged, and the damage is not instantaneous. Unless the enemy is held down by other CC, more often than not people just Flash out of it. More often than not, its a half-assed Execute that doesn't even work that well. The Ult is ultimate trash until you get Rylais and even if you have it... nothing to stop people from simply Flashing out of it. ****Meanwhile, Lux's R has much shorter cool downs, way more range, way easier to use, and does more most of the time. Its instantaneous too. BOOM. No awkward Chaos Storm to micro and bug up... you just point and BOOM.
Poke Lux has better poke. Viktor's E does more damage but only if BOTH parts of his E land on multiple enemies; no one is going to stay there for that to happen, Rylais or no Rylais. Meanwhile, Lux goes E... BAM!
Build Flexibility Lux is more flexible. Viktor needs to upgrade his Core and he needs to have Rylais to be of any use. Meanwhile, Lux can afford to do different types of builds depending on the situation (ex going Abyssal or Zhonya is certain situations). Any deviation from Core + Rylais for Viktor severely impacts the usefulness of his abilities.
** Number of usable abilities** All 4 of Lux's abilities are useful at all stages of the game. Viktor's R is utter trash without Rylais (and people can still Flash out of it with Rylais)... Viktor's W is no use offensively... Viktor's Es and Qs rely on upgrades. So most of the early and mid game, Viktor basically only has 2 useful abilities compared to all of Lux's.
Lux has way more utility This one is obvious. She can slow, she can shield, and she can bind. Viktor? The only CC he has is his W and its basically useless offensively (and defensively, its buggy and unreliable as hell).
So why is Viktor played so much?
Isn't he basically a worse, clunkier, more short-ranged version of Lux?