Those skill shots do reward them, its called more damage. Ziggs Q can easily hit 700-1k damage lategame, and if you are in a minion wave you will get hit due to splash damage. Vel Q not only hits good damage, it slows and almost always is followed up by the rest of his kit meaning a quick death if you are anything but full hp.
Hell Morg E probably hits even harder, if you don't have a dash and they place it on top of you, thats almost always going to tick 3 times. Late game you are talking 150-300 a tick, so 450-900+TLD and you easily do over 1k just from only a PART of it hitting. Kicker is? It heals Morg too, and works like a nightmare with Rylai's.
Lux E? The highest I ever saw it hit for was maybe 500. All it is good for is poking down which it takes several before her Q+ult becomes lethal. I can't be bothered to look at the scaling but I am fairly sure its one of the weakest.
So please, Why is Lux's E is one of the weakest mage poking tools but is cried about? Since its a big AoE? Last I checked, usually if something does a lot of damage, its usually hard to land, but if something doesn't do a lot of damage, its easier. Lux is on the later side.
If you are having trouble with Lux, then outsustain her. Its obvious as day when a Lux will E. and its with you near minions. Don't get near minions or try to bait it. Hell harrass her, you can easily bully her and she has no health pool so she is easy to bully out of lane. And if she doesn't get fed, she isn't waveclearing, and she can't CS for crap under turret.
Like in all seriousness I just seriously can't comprehend why people think she is so damn broken. Because of her E that not only cost a fair bit of mana, but doesn't even hit hard. And if you are letting her proc her passive that is another story. This is the only time I ever seen Lux as anything but support(and even that was rare) and it is due to Riot making S6 so stupidly snowbally that everyone is extremely safe and passive. She likes safe and passive so that is the sole reason she is back. Otherwise she wouldn't be played. Also you realize if she did receive nerfs, she would get compensated elsewhere? Do you want her Q snaring you longer or hitting hard? Or her shield being stronger? Or her Ult hitting harder? I love fighting Lux but I would hate if her shield or Ult got stronger due to her E. Hell if her E had a smaller AoE but hit way harder would be bad.