A Theme i noticed with recent balancing patches nearing worlds.
TLDR is the last paragraph.
No this isnt a LC$ Big plays complaint thread first of all.
I think on some champions Riot doesnt specifically like their current situation and they are trying to fix issues in their kit caused by item changes, Even if they are sitting on an okay winrate. 2 Big examples being Yasuo and Vayne.
I actually saw someone saying Yasuo is being buffed because LC$ and i just had to laugh since i think the last time Yasuo was picked in worlds was the season he was released.
Anyway I will be focusing on those 2 since those are the 2 talked about on the boards the most recently.
Yasuo - Currently a Top Bruiser. IMO Yasuo is much more fair to both him and his opponent in the mid lane. In top Yasuo gets bullied by almost every melee pre-6. But Yasuo has an easier time avoiding trades and poke and can just farm until powerspike. As well as Top Yasuo builds bruiser and not melee carry which is probably healthier.
These recent changes were to give him a bit of base MR (Not too much a big deal) to help him survive poke mid, so that Riot can start pushing him back there. The Ult change most likely was to help follow up on midlane ganks.
At the same time though they nerfed Yasuos shield, this was to make his early game slightly weaker. NOW most mage poke abilities will actually poke through Yasuos shield early instead of just glance off but pop it. Overall i say this wont change Yasuo too much (dont worry he isnt going to spike 5% winrate in mid hes currently at like 48% in mid.
Hopefully Yasuo will go mid and maybe be less bruisery after these changes, hes healthier overall that way.
Vayne - Currently a squishy killing monster at 2 items. Vayne is supposed to be THE tank destroyer ADC. There were many threads overall about this. But we know the 2 silver bolt on Q was a bug. And with the inability to crit on Qs, and the Silver Bolts getting increased scaling they overall solidify her as more of a tank killer again.
As for the Health on kill. This... i really dont know about. She wont be getting more than like 800HP or so per kill late game, and since her like ONLY weakness is late game is CCing her until she dies. I guess this is to make it easier to survive after taking harass for FOCUSING the tank she was supposed to? I really dont know but i am guessing thats what they want.
TLDR: Overall these changes to semi 50% champions are to change how they play because Riot didnt like their current situation gained from a lot of Item changes this season. Vayne is supposed to be a tank-killer not an assassin. Yasuo is supposed to be a mid lane Melee Carry instead of a Top Bruiser. I expect we will probably have a few other changes before worlds trying to fix some gameplay styles that Riot disapproves of even though they are 50% winrate.