@Riot I have a suggestion to get new players immersed into lore

When it comes to lore I find that the easiest and best way to get people immersed into it is in game events. Like when Vi and Caitlyn ult the same person and unique dialogue plays. If this could be put on a larger scale and have the references involve pop culture and various players in the Lol community then it will entice people to become more active community members.

In Game Dialogue Vayne kills Shaco or vice versa and the one that dies says "Only you" instead of his usually death animation quote. It's a subtle nod at the Arkham Series

Events When there are 4 or more yordles in the same game and the timer has passed 40 minutes you'd get the "Yordle Paradise" event. Whoever wins the event gets a small aesthetic change to their side of summoners rift. Something like a small mountain of cash in the fountain. References the popular parody of "gangster paradise"

Random Monologue A random one liner that a champion says when specific conditions are met or at total random. For example, at the beginning of every tenth game with kassadin he begins the game by saying "Xpeke". Plus it's a nod at Esports, self promotion.

Subtle Enhancements More stuff that's a subtle enhancement or something that stays in the buff bar. Draven and Darius on the same team? Small buff that says Super Axe Bros

Squad Bonuses Some form of acknowledgement that you and your team are all rocking matching skin sets. Like if there's one team with a full pool party set then baron has a floaty.