My biggest disappointment with the retcon is that the old lore was one of the coolest ways of doing gameplay/story integration I've seen (in recent years if not ever). I'm really sad that Riot decided to axe that when it's something the industry needs more of not less.
I don't understand why they haven't pushed the connection harder themselves, something like Factions would have been amazing as an official game mode and way of storytelling from Riot's side.
They had something really capable of a lot of innovation here, and decided that it was... too difficult? That they wanted to do something else instead? You don't just destroy something because you wanna make something else, not when it's made for others.
Personally I hunger for more gameplay/story integration all the time, explicit gameplay/story integration.
When you're making a story for a game, or a game for a story, or both in any form of tandem with each other, they should feed into each other, like how we presume Riven is the killer of the elder in Yasuo's lore because of an ability only shown in gameplay. (Wish I could think of more examples here, but I don't have the time)
/disrupt rant