a higher win rate in solo queue, where any competent player can trash the lower levels with a skill-based champ. Evelynn, however, can't take someone out if she unloads her full kit into them unless they're ridiculously out of position
I will paste my other comment here
evelynn can't do anything because riot nerfs her into the ground and refuses to remake her. Her E isn't even relevant to her standard build and only benefits AD eve. Her ultimate works on %current hp and gives her a short duration shield. her Q could fire 10x early game and not take out an enemy, meanwhile most junglers can kill you by themselves and even easier if aided. In addition, Evelynn has a very low gold income because if she snowballs herself, she dooms her team...
A full build evelynn is completely irrelevant to even a half build late game team...she couldn't even kill an out of position veigar underneath of her team's tower because he benefits from her primary stat...
a competent lee sin, rengar, master yi, sejuani, chogath(he can jungle but why, idk), akali, ekko, warwick, literally everyone else in the jungle could kill that veigar...