The person who plays lux support personality is most likely atrocious, and they will feel the need to ruin/take your cs often and make it a concern of theirs to get caught and go in when it is unnecessary (aka give free kills just by playing super dmg solo carry with no farm). The lux support species also likes to say 'its just normals' even though you might be trying to play a fairly serious draft game.
I'm sure I'll remember some other downsides to them, but needless to say, the lux support species is usually always frustrating to play with. Take caution or you might regret.
In my experience, Lux is almost always terrible if she isn't playing mid. If I ever have her support me, she usually can't do too much other than steal creeps. I remember once a guy was trying to play Lux mid; however, someone else called mid. Instead of choosing a different character, he decided to just tack himself onto top lane with me (playing as Malphite, who really needs all of the creeps in order to do anything on top lane) and steal all of the creeps. Even though he berated our mid most of the game, our mid did pretty good... but we still ended up losing.
So yeah, I agree. Lux support is usually annoying and often time just some guy who is butthurt that he couldn't go mid.
I honestly despise people that think they can play Lux, they usually fight an akali mid and go on a massive feeding spree at level 6. Or if they're support they'll attempt a skill shot, miss and wind up being stunned/grabbed/rooted instantly, every time.
"In the beginning the universe was created. This has made a lot of people very angry and has been widely regarded as a bad move."
I play Lux support. I do not steal creeps. I am not atrocious. I do not get caught (okay, I do get caught sometimes). I don't play Lux Support because I'm butthurt that I didn't get mid, I play it because it's fun as hell and the poking/zoning is atrocious if I'm not being a total idiot with my skillshots during play.
Don't define a champ's skill at a role in 2-3 games with trolls/bad players. Play it with someone like me.
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Really though anyone in randoms, be it ranked or normals that is playing a mid as support will feed and try to build like they do in mid. They will not ward, grab any GP 10 or actually bring support summoners. they don't support its an excuse to play a champ they like in another lane.
the list includes but not limited to: Lux, Morgana, Fiddlesticks, teemo, zyra, etc.
I've never not had a lux support be detrimental to laning as an ADC. She is very good at taking basically everything from you and leaving you dry. A lot of ADCs cant burst steal a kill compared to the quick long range burst of her ult and E.