Patch 7.4 was a mixed bag for professional play. Some champions, like Ryze and Jhin, just got slapped on the hand. However, other top-tier champions received pretty massive nerfs. On top of that, Riot's finally addressed some of the itemization outliers, nerfing armor penetration in order to reduce the effectiveness of the ubiquitous lethality builds.
Grounded and de-barked
The biggest change in the new patch went to Corki. He's lost a ton of damage from his regular missiles - both bases and ratio - while receiving some very minor buffs to his Big Ones. On top of that, Corki gained a secondary resource bar that displays when his Big One is primed, giving opposing players a heads-up when he's ready to lay on the pain. With his ability to consistently poke down enemies reduced, Corki is likely no longer a contested pick. He might still show up in certain matchups, but most pros will likely ditch Corki in favor of different champions likeTaliyah or Aurelion Sol.
The only other champion to receive some pretty major nerfs was Maokai. Arcane Smash's mana cost now increases with level, and Sapling Toss no longer damages units in its landing zone - both changes that reduce the Twisted Treant's ability to waveclear safely. While it's doubtful that Maokai will drop from the meta as a result of the nerfs, he may no longer be as high of a priority for teams. Nautilus will likely step up to fill Maokai's spot as the tank of choice, and it's possible that Sion may put in a few more appearances as well.
Not so lethal
Substantial changes in 7.4 were directed at items. The Black Cleaver now builds out of a Kindlegem and grants less attack damage, making it not quite as attractive to the squishy champions that were buying the item in order to counter tanks with lethality. Lord Dominik's Regards meanwhile has become less-tolerant of the purchaser's health in order to get damage, making it a non-bo with the new Cleaver. Both of these changes mean that champions trying to stack armor penetration with lethality won't be as effective against tanks, and will need to actually itemize for tank-busting if they want to cut through health. It's not entirely clear if this will reduce the prevalence of lethality builds, but it's likely to at least reduce the strength of champions like Quinn or Jhin.
