I compared each LoL champion's winrate across Bronze, Silver, Gold, Platinum and Diamond to see which champions perform relatively better at high elo compared to low elo. This list is the 10 that are most improved with more talented players.
#5 - Rek'Sai
She's a complicated early-game snowball jungler who's a great duelist and has a lot of map pressure. Also, she's a woman!
Here are Rek'Sai's winrates across the board:
Bronze - 42.89
Silver - 45.61
Gold - 47.44
Platinum - 49.42
Diamond - 50.82