3 of the hardest champs in the game are tier 1 with a 52%+ winrate

What happened? I thought hard champs would have a 47-49% and a low pickrate just because they are hard to play, and, come on, 90% doesnt like hard champs, they would rather pick an easy-mid difficult champ, but why is riven the most picked toplaner, and STILL, the highest winrate in the game? Why vayne is at 52% winrate with a HUGE 13% PICKRATE? Wasn't vayne one of the hardest ADCS? Not even talking about zed, He actually have 52% winrate with 12% pickrate, am i being dumb, or this is soo wrong, and unhealthy for the game?