I read a few weeks back that Riot Ezreal was looking for suggestions on how to make the lore better in League and after some thinking these are my humble suggestions, up for discussion by the subreddit.
"leg·end: One that inspires legends or achieves legendary fame."
We play a game under the name League of legends, but the legends of these select champions are sorely lacking. While some players might not enjoy or care reading on the history of every champ, adding in a deep and expansive lore to the existing and future champs will only make League look more enticing to prospective Summoners. How do we do this though?
Add Depth to Existing Lore and Champions
One thing that Riot needs to preserve in whatever they do with the Lore from here out, is the stories that they already have. People have connected with champions believing in the story that was originally connected to that champion. Reworking the lore for every champ would only leave a bad taste in the mouth of people who enjoy the story of their main champion. So how does Riot make these legends more engaging to read? We must go deeper.
We all have champions that we enjoy playing, and some that we will never play. I will probably never, ever play Poppy in my time in League, but there are a few people out there that have her as their main. Why not reward them for enjoying Poppy? Add in specific lore that unlocks once a number of wins/games played with that champion is achieved. What does this do? Allows people who enjoy champions to delve deeper into the lore of that character, while not burying the rest of the community with lore that we didn't want to read in the first place. Every champ would have the amount of backstory that they have now, so that new Summoners can read and enjoy their new characters. But as they play more with those champs they could learn more about their favorite legends. Dyrus would know exactly what Singed's posion is made out of. Best Riven NA would know the story behind Battlebunny Riven. Riot could even throw in champion specific Summoner Icons once a champion's lore had been fully experienced.
Once Riot implemented this new, deeper lore, this could open the door for more in-game interactions like we have seen recently with the likes of Rengar/Kha'zix. In-game interactions could be reflected in new pieces of lore. One example that comes to mind is the fact that Irelia almost died in an Noxian attack on Ionia. Whenever Irelia plays against/wins against/kills a Katarina, Darius or Talon there could be an in-game rivalry that begins, or a piece of lore would unlock for Irelia after the match. This could further the lore that Riot wants in the direction that they choose, while promoting greater interactivity with it.
Expanding the Lore
From my understanding, the League exists as a political peace treaty between the city-states that is there to settle debates and disputes. Other than that knowledge, what does the League actually settle though that we know? I can't think of one Summoner who didn't enjoy the Noxia/Ionia in-game event, why not bring it back? Have monthly/quarterly Valoran disputes that the League settles through battles. Riot can implement a "posting board" where they lay out the two city-state's arguments for coming to the League. Pre-picked teams of 5 champions can battle against one another on their side's behalf and whoever wins at the end of the time frame has their side decided. Riot doesn't have to make a new item (Boots of Luciditiy), but the lore could be changed to reflect how the community felt about the topic. Granted, this would put a lot of power in the community's hands to affect the future of lore, but if Riot wants that, it could be pretty fun as well.
Say the month's "Dispute" is that Demacia thinks that Caitlyn overstepped her boundaries in punishing a Demacian citizen who committed a crime in Piltover. Teams could be Pilt: Caitlyn, Vi, Jayce and a few other champions (who for reasons Riot can explain think this is the right choice) against Lux, Garen, Jarvan and so on. Summoners could choose if they wanted to participate in the month's "dispute" or not, but those who did would get to enjoy fighting for their cause and seeing the outcome at the end of the allotted time.
So those are just a few ideas that I've been mulling over on how to put the Legend back into the League. This forum loves to debate a good topic so I hope this is enough information start a conversation.