130 mana on Lux's E is too high, plain and simple. And with the upcoming mid-lane mana nerf for 21/0/9 build mages next patch, it's only going to get worse for her.
I keep asking this of you, but you keep refusing silently. Stop ignoring.
360D3GR3SS2 votesIf you are legitimately thinking this is a substantial nerf, it isn't. She has 334 base mana @ level 1 and the proposed change is to give 1.5% missing mana per 5 seconds instead of 3 per 5 seconds. In order for this mastery to restore the same amount of mana as its 3 per 5 she needs to have 200 missing mana. Considering that her mana bumps up to 1184 at level 18 this is not only a simple task but you will often be regenerating nearly triple and usually double the 3 per 5.
darkdill2 votesYou missed an important part: Meditation is switching places with Expanded Mind.
You'll need 12 points in utility to get Meditation since it'll be a tier 4 mastery. You won't be able to get it if you go 21 in offense.
The tier 1 mastery is going to instead be +75 maximum mana instead of +3 per 5 mana regen.
360D3GR3SS1 votesAH touche, Honestly I do not feel she needs mana changes. Her kit is extremely strong and I do think she needs to prioritize mana items because of how much utility and damage her spells give her team.
darkdill2 votesShe's outdone on the utility front by Orianna and Morgana, and outdone at damage by Ziggs and Xerath. Doesn't leave Lux in a good place.
Also, compare how often Lux can use her spells to someone like Leblanc. Leblanc is a mobile burst assassin, but has better mana longevity. Doesn't that seem wrong to you?
360D3GR3SS1 votesShe is not. Ori has a slow shield and her ulti. Lux has a double root slow and AOE shield. Ziggs has far less burst than lux same with xerath.
DrNova1 votesWhat nerfs?
Angry Monster2 votestheir are no nerfs. Riot is moving the utility tree around a bit, changing power levels ect. Riot has already said that the first pass will probably be under tuned and will see how it effects actual game play and will make needed changes.
The op is a tool that goes off everyday.
Neo Cyrus4 votesWith the mastery tree re-arranged those who want to go 21/0/9 for some mana get shafted, in other words mages. Regardless of how anyone tries to spin it, it is a nerf to mana mages, after season 5's base stat change already thoroughly nerfed them.
DrNova1 votesAh. I go 21-9-0 on all my mages cept ahri anyways, so maybe i wont notice
SantanaTheSlick 1 voteseh i played with lux before her mana cost's she was a terror in lane. Her mana cost's only keep her form being a pain the in ass. Plus that ult cool down is really stupid.
darkdill1 votesYou want a painintheass? Try laning against a Xerath. Not only is his damage better than Lux, he also doesn't have mana issues because of his passive. Plus he can stun you, unlike Lux (who can only snare you).
Or you could look at Orianna. Goddamn that ball is annoying.
Dr Poro1 votesWhile I strongly agree that her mana costs are too high (130 on a basic ability), I don't really like Lux to be strong as she's pretty annoying to lane against with that E poke and strong burst. I just don't want her to be season 2 level again.. But I think a small mana buff is appropriate atm.
darkdill1 votesYou didn't have Zed back in Season 2, and Katarina wasn't nearly as dangerous because she didn't have Sinister Steel. Nowadays if you see an enemy Lux, you have plenty of counterpicks to choose from.
Non-mid lane counters include: 
