Well, not really, I did read it, but had to wonder why I did afterwards. As far as I'm concerned, if the game doesn't have a good story, I don't pay attention to it. It's obvious Riot isn't really trying anymore either: Many of the newer champions like Lissandra and Syndra don't even have justifications for being in the league.
Lissandra is doing what the League's intentions are: to solve political disputes through combat among heroes. She wants more power in the Freljord despite the in-universe public not understanding that Ashe and Sejuani's sister who was their sister Lissandra is not that Lissandra anymore, but the soul of an ice witch from a long time ago attempting to take over first her country then the world.
Syndra likes to be magically powerful and is an antithesis to traditional Ionian spirituality, and thus an unexpected political threat from the inside. If her justification is simply, "I wanna kill people and look good doing it!" That's fine, but I think she offers an option for lore later to justify a champion who is Ionian but works for Noxus outright, under Syndra's discretion.
Quinn and Valor had a huge long preview thing that was spread out over some time. A ranger in the form of a falconer team is an interesting concept they pushed, especially considering that Demacia is supposed to be, in-universe, against doing subtle things like scouting and hunting assassins with what is basically their own version of an assassin because that's NOT HONORABLE
. Yet she crushes on Jar-man Episode 4 who is the one given her the explicit permission and order to do it.
Zac had this drawn out series of experiment notes that culminated in the researchers saying "We love him too much!!" and pulling him out, giving us an example of Zaun not ALWAYS being the fucked-up evil mad science counterpart to steampunk Piltover. He's like, the opposite of Mundo in that way. Pretty wacky. Also sounds like Taric's VA. Slime is outrageous, too, I spose. He also has one of the most unintentionally hilarious lines. It's supposed to be just a little joke, but the innuendo makes it spectacular. "Fighting is in my blood! ...I mean, my goo."
I like Viktor's reason for being in the League a lot: he's advertising! "Hey everybody! Be a robot! Look, three arms rock!"
Riven's story is muddled, but I think the gist of it, from browsing the new website's beta, which shows champion friends and rivals, is that Riven believes in the freedom that Noxus has so long as you are strong in pursuing it, and was a fervent warrior in its system. She probably has wicked mad girl-boners for Darius, or at least did before he helped Swain. However, when she found out about Singed and Swain (her rivals) doing shit that didn't benefit Noxus by being directly in the line of fire of Singed dumping chemical weapons on Ionian troops not giving a shit about the Noxian troops (including her) right there next to their enemy, she thought her city basically fell from grace. Her leader hired a mercenary and the two of them did shit that only benefited themselves. So she broke her sword to signify her disconnect from Noxus and joined the League for protection. Her ultimate makes her say shit like "There's no other way..." which means she regrets using the sword's magic to be pulled back together, but isn't an idiot and wants to stay useful to the League.
Skarner is muddled a bit too. He's scary because he was a warrior, but sometimes I go :0( when he says "I miss my kind..." I am not sure what they should have done there, to be honest. Being a scorpion is cool, though, so. It's okay.
Contrast Diana and Vi: home-runs as Champions go, to be sure. Both have kickin' rad songs, extremely deep, engaging personalities and purposes, and backstories that make their in-game personalities and attitudes applicable to their gameplay mechanics
. For a video game, that's basically everything you want for your character.