They didn't retcon the setting. They removed it.
And part fo their reasons for doing it were blatant factual errors.
Don't forgive them for being awful at their job or lying to your face.
And don't say it's ok to leave the setting hanging for a year.
The old lore was focused on an entire world, with an ongoing plot (also, way to leave out the other Fields of Justice, shame on you). The story was centered on the game and driven by it because, hey, it's lore for a video game that's the natural state of things.
The new lore where summoner's don't exist simply doesn't exist because they removed the setting and any ties to the game.
And that's when it stops being lore for a video game and starts being a random collection of short stories, no matter of glossing over it on their part, lying to our faces about their own story (or just not knowing their own story in the most incompetent way possible), or being pampered by people who clearly didn't know the old lore really well at all either.
None of that will change the fact that they said they were gonna do a bunch of stuff, that a bunch of stuff was now the case. And then left it there for the next almost year (and counting).
The bilgewater event takes place in their new, non-lore, game-unrelated AU, and it's hyprcitical of them to let their spinoff stories influence the game in any way, because the entire premise was that tying the game and the story together was too constraining and difficult.
The story they're telling, isn't League of Legends' story, it isn't the same story they were telling before in any aspect, it doesn't actually have any grand setting-wide plot holes because there is no grand setting because no such thing has been detailed yet for the last soon-gonna-be-a-year that they've had to release a pretty simple run-down of here's what's changed and here's what's the same and here's how everything happened instead.
They're not telling the story of a world and it's major players, with a fairly unique and even somewhat innovative premise. They're telling the stories of a bunch of fantasy stereotypes doing mostly cliche fantasy things.
The rebirth of Shurima is a really cool story to set in a world where you are provide ongoing tidbits about the state of politics.
It's rather shallow as the end of a story about raiding a tomb and unleashing evils (and a good or two) sealed in a can in the most cliche manner possible.
And for all you might cry and Riot's storytellers might claim that there's gonna be more Shurima stuff coming and that last year's even was just the beginning of Shurima's story. It's been almost a year, which is a fairly long time to ask someone to wait for a story to move on from its prologue. It's also a really long time to take in laying down some really basic setting details (like what about the rune wars? why isn't Valoran blown up by the next one when the IoW and the LoL isn't created to prevent that from happening? What about Noxus' invasion of Ionia, how does that happen when they're not safe from Demacia invading them? How does it play out when Ionia can't halt it by joining the League? Did Kalamanda happen? How did it happen? or did it not happen and Skarner is just a generic monster scorpion tomb guardian now?) There's a lot of questions which is not something they can take their sweet time telling through youtube shorts and huge yearly events. A lot of these things are stuff they had to answer right away to have the right to a tiny shred of respect from their customers, and it's been a year (almost).
And the most important thing to answer after retconing the League out of it's own lore: What is the League of Legends?
And that is the one thing i'm confident won't be answered for years until they forget some really simple fact about their story (or just no longer like it) or just simply wanna tell a different one and decide to scrap everything and start over with a new 180 turn in direction.
I'm sure we'll get more stories from Riot Games. Just as i'm sure that none of them will be relevant to their game, even if they'll use some of the same characters in non-game incarnations.
It'll not be lore. Lore is something which expands on and explores facets of the world belonging to a video game. The new story, thoroughly disconnected from the game in an attempt to act more professionally, is not Lore.
Anyone saying otherwise is (intentionally or not) decieving you.
For what it's worth, what little of the new story material i've read i've thoroughly enjoyed. Sion's little segment, Kalista's video, the Harrowing video, Bard's champion reveal video, Ekko's champion reveal video, Ekko's random comic, Tahm Kench's champion reveal video, and even what little of the Bligewater event stuff I could be bothered to read before losing interest and moving on to a real fantasy book i'm currently reading.
I've liked it all, and loved some of it. Sion's stuff, Ekko's video and Tahm's Video are really really great.
They're just meaningless out of their own little existance because there's no setting to tie them to, and no actual connection to the game they're created for.
I've stopped playing league now, finally (atl east trying to), because while I love playing, I hate the game.
I was bait-and-switched, came for the story and great character design, but stayed mostly because I realised the story was excactly what I'd been dreaming for in a video game story... except much more in-depthly so.
And then they took that away for mostly flimsy and some objectively bad/wrong reasons, and it's caused me so much mental stress and sleep-rythm disruption over the last almost year.
I hate the game now, and I hate it's creators. Most of all I hate the storytellers, not as people (I'm sure they're great people, at least that's my impression from the red posts i've seen), but as professionals. Because their work is causing me pain, stress and nothing else.
There's so many other things I could do with my time. Like read up on the lore of a game I'l be playing in for the next year, a game with actual setting.
P.S. This is why you shouldn't make long replies at me. Also why I shouldn't be replying in them iddle of the night.
P.P.S. To any reds: At least give Factions a thorough community spotlight before you remove the rest of the lore, it's well deserved. More so than any other community project I can think of, because this is lore-continuation(so fan-art and fan-fiction I guess), game-mode and community engagement all in one.