Greetings, Citizens of the Internet!
Today I want to talk about the lore (duh, it's in the title). The thing is how lore has changed and I will also talk about some of the general statements I hear about this change, mostly discussing about why statements about the lore being bad is a bad statement in itself.
Veterans go to the League, Newcomers go... somewhere?
As most people noticed who has been around before the Varus-release (the currently newest champion who has the League mentioned in his lore, although it's implied with Draaaaaveeeeen), Lore is about how badass, dramatic or powerful a new champion is (like always), but doesn't directly state any reason why they join the League anymore. For fellow citizens of the city-states that are more than capable in fighting, you can assume that they joined the League to represent their city-state, but of course, we've gotten more "independent" after Varus. Like Syndra, who hates Ionia and literally lives with her head in the clouds. She is all about unlimited power and might and she demonstrates it in... well, a place where Summoners are summoning champions like pawns and said summoned champions have restrictions upon them and are also protected so they won't die permanently, essentially making unlimited power point- and useless.
But is this bad lore? Absolutely not. Looked at itself, she's got a pretty well-done (if somewhat standard-ish) lore about a girl with great potentials that misunderstood the Ionian (read: asian) way of helping ("You want to eat? Have a rod and learn to catch fish!") for betrayal and envy. A classic kinda-sympathetic antagonist for a RPG-story, wouldn't you think? So what is the problem here? It's not bad lore, but it is ungrateful and/or clumsy lore. She is a great character fluff- and crunch-wise, but she is in the League just because. Mind you, I'm talking so much about Syndra because most other champions with no mention of the League in their lore can have some reasons nonetheless (and fans can be very creative when something needs reasons). Jinx, for example, seems to profit from the League because it gives her the positive aspects of the status quo. She can blow up stuff like usual and troll Piltover much more effective than without the League.
"New lore is bad game's ruined 4eva!" SHUT UP AND LISTEN!
Listen, dear new-lore-haters: I enjoy lore as much as the next guy, but this is a game that had an excuse plot to begin with. Big wars, eternal rivals that have the quantity and quality to spread their hate over the entire continent and then the Institute of War where some guys decides the fate of the city-states? No amount of good writing can cover the fact that it's still an excuse plot. But I'm okay with it, because this is a competitive multiplayer game, where the only other possible solution is no plot. You can't write stories in a competitive multiplayer game the way you can do in cooperative or singleplayer games because the state of the world has to "reset" after each match. For a deeper analysis about this topic, go to Penny Arcade, then to the Extra Credit-show, Season 7, "Competitive Storytelling". Yes, I'm throwing in some shameless advertisement because I'm too lazy to paraphrase something these guys made.
Anyway, when you're going into a competitive multiplayer-game, don't expect great stories. And if you meet great stories (LoL's got some, believe it or not), be grateful for it, because it IS the exception rather than the rule. Plus they handled the crunch-elements of the Rengar/Kha'Zix-rivalry in a smooth way without affecting gameplay too much, which is a great feat for such a game. Again, I welcome you to watch the above-mentioned video for the topic about "How fluff-based rivalry made into crunch can ruin a game if not done carefully".
Jeez, I better stop here before I make a whole section about mentioning that video...
Why even the tiniest amount of lore enhances a game
Simple: Listen to the quotes of champions that doesn't refer to pop culture. Outside the lore, they have their own story to tell, their own history. You can see some relationships you wouldn't see without knowledge of the lore. If you joke as Garen near an enemy Kata, you may see him how he tries to impress her with masculine prowess. That's some story. I'm not too fond of the Garen/Kata-ship (I'm still sure about this being nothing more than a misunderstood joke from that Blitzcrank Love Compatibility-thing that since has gone in entirely new directions), but it's not done to undermine the personality and character of each involved, so I'm quite okay with it.
Just remember: Lore or characterisation needs to be consistent to enhance a game. Even Samus from the Metroid-series has a solid and proofable character despite being mostly silent and doing nothing more than blasting extraterrestial dangers (which is one of the reason why Other M flopped, but let's keep that can of worms closed or we'll be here all day. If you want to discuss about it, hit the Metroid-wikia, they're more experienced with the topic and the game).
That's all, folks
Well, that's it. Feel free to hate me in the comments because I'm a hippie who is unable to hate stuff and needs to protect even the worst stuff in your eyes XD
To be honest, I had some more thoughts about this topic, but I kinda forget about them somewhere while writing this stuff.