"League of Legends" has been known for implementing such buffs and nerfs to balance the meta of champions and maintain a proper rotation wherein there would be no overpowered or op champions that can be used during matches.
"League of Legends" update 11.3 includes some of the buffs and nerfs on such champions. Riot Games regarded the changes because some champions needed to be strengthened and powered up, while some need a downgrade in terms of in-game skills and effects to keep the balance.
On a Blog of Legends, it listed some of the game's champions that are the best candidates for such buffs, and also those which are being the best candidates for nerfs. And here are some of them:
Corki - Buff
Dubbed as the Daring Bombardier, Corki has not been picked by players, especially those in the pro scene. The ADC champion could be regarded as an inconsistent champion during games, wherein his skills could go hot one time big time, or might not take effect at all, Using him would require much precision and more in-depth skills, yet with a buff especially on his handles, he could go up to a C-tier or even a low B-tier compared to his eventual rating today (or on the last five patches) listed as a high D-tier champion.
Camille - Nerf
Probably one of the best champions for an already long time, Camille's outstanding top lane performances on the pro scene has made her to be included on the S-tier of all top lane champions in the game, meaning that she is being picked in an almost staple status, or an automatically banned champion as well. Seeing her being nerfed down can somehow balance the game a little bit by which players may get to pick the other top lane champions available in the game.
Vel' Koz - Buff
A multiple role champion that played as either a support or mid role champion, Vel'Koz also did not see any pick in the pro scene. Even if its skills could provide in-game effects to the enemies, its stability can easily be torn by high-damage inflicting champions such as for the assassin and ADC heroes. Buffing it up may see Vel'Koz potentially being picked on the higher tier games, where it could be utilized especially as a support role champion.
The Melee Tank/Support champion Leona has been often the favorite picked during the pro scene. However, this character has been banned many times. Its durability and life-regenerating capabilities could be useful as ever, especially in team fights, not to mention her steady damage being an efficient factor in finishing such enemies during multiple fights. The S-tier support can see a nerf anytime soon, with the next update as mentioned by Comic Book could see a champion rework in the near future.