From Riot Phroxzon on X (source)

Items
-Bami’s and Sunfire have been pretty weak for quite a while. So we’re buffing the Sunfire line by putting a decent buff into Bami’s.
-In particular, many of these champs don’t optimally buy Sunfire first, which kind of defeats the purpose of Bami’s as a component.
-Mercurial has also been pretty weak, so we’re giving it a net buff
-We’re really happy with where Yunara has landed overall.
-Now that her Mastery curve is starting to catchup, she’s pretty overpowered though (mostly for Elite/Pro) and there are 2 key areas that seem immediately off that we want to correct now
-The first is how strong she is at early levels with high E movespeed, Lethal Tempo, Q reset and range, especially given her scaling profile
-The second is her E uptime, especially later in the game, given that we kept a few mastery moments in like ERE, E being off CD when R wears out, etc.
-Long term, we want to move her off E second max as Pros and Elite players unsurprisingly use this spell ~30-40% more than regular players and it’s very powerful in ways that aren’t immediately obvious
-Base W is also paying costs for it, being a spell that feels limp for the majority of the game (it’s actually pretty fun when this spell does damage)
-After the changes to Illaoi a while ago, her tentacles can sometimes unsatisfyingly fail to slam on a spawned E vessel. These changes aim to resolve that case, but as a result require a bit of a compensation nerf.
-Now that Briar has hit her mastery curve saturation point, she’s a bit too fair in higher levels of play
-We’re making some changes to her ult that lower its counterplay a bit, but compensating by lowering her damage when it hits (making her a bit less feast or famine)
Mid Meta
-The mid meta has been a lot about tempo AP champs (Annie, Aurora, Galio, etc.) who also build pretty tankily while also having a lot of damage. This results in them strategically not having a ton of tradeoffs, so we’re making a few adjustments to these champs that skew them a bit out of Pro
-For Annie, this is moving her more on to Q max, which is already her most popular solo Q build and nerfs the W max that most Pro Annies end up having before their Q is maxed
-For Aurora, nerfing some of the Liandries oriented builds that allow her to do a ton of damage while also being very durable and getting a lot of passive procs off. This build is pretty hard to play against when comboed with a lot of her trickery tools
-We think the burst build is pretty balanced, so it will be a bit of a nerf in the early game, but ~even a bit up later on in the game
-Azir is also just too strong of an outlier, especially after his 15.14 buffs
-Cassio could use a bit of a buff relative to where she is today to be a decent pick late in fearless against Sylas, Galio, Ryze, etc. type champs
Qiyana and Sylas
-Overall, we’re pretty happy with injecting some of the novelty back into the jungle with these champion picks.
-However, they’re too strong, especially in Elite, so we’re taking some of the power out here.
-They don’t need to be stronger than their primary roles.
-Despite Kraken, PD buffs, Ashe hasn’t picked up too much viability.
-She does seem sleeper strong though, so not going too hard here.