Riot should've closed the League through writing rather than a retcon.
You had the story in the perfect place to get rid of the League: LeBlanc and Swain were already plotting together. The Black Rose really doesn't give a damn about Noxus; they very well could've been scheming to sabotage or destroy the League and bring back all-out war to Runeterra for their own ends. It would've been really interesting seeing where you went with it, especially with the lead up to it.
But you didn't do that. You retconned it.
We could've found out what happened to Ashram or who/what Jax is. You could've wrote in a scandal that obliterated the League's political influence, leading to its eventual dissolution.
But you didn't. You retconned it.
Brand and whatever other terrors the summoners had imprisoned could've escaped, damaging or destroying the Institute and ruining the League's credibility.
But you didn't do that either. You retconned it.
All the outlying champions (Zed/Syndra/Jinx or the Void/Shadow Isles factions) who would react aggressively to the League's sanctions and attempts to control them could've attacked the Institute.
But you didn't even do that. You retconned it.
Yeah, I know that the League of Legends was a poor framework that you only invented for the game, but the thing is that you had put so much effort and love into the lore that it actually became good. The Judgements. The Journal of Justice. Ionia vs. Noxus. Nothing you've released in the past couple years compares to the quality of writing you used to put out. The Freljord event? It was decent if you ignore the destruction of Volibear and Trundle as characters. You made Trundle as absolutely generic as possible, which is especially sad considering how his original lore broke the 'I'm-a-generic-fantasy-troll' archetype. The Shurima event? You actually removed content in addition to retconning several characters in order to shoehorn in Azir, a character who is totally devoid of story or realistic motivation.
Please come to your collective senses.
Please.