Yi cant 1v1 a decent vayne.
Yi gets fked by shaco, jax, ww etc.
Yi gets fked by melee supports, he cant even reach an adc with an alistar, braum, leona supp.
Yi gets fked by other supports, he cant even reach an adc with a lulu, janna, zilean and I am not even listing nami because for that you have to be good at landing the bubble the others which I mentioned are simple enough to even first time them.
Yi gets fked by 90 % of the league champions, you just have to bait his ult. he cant chase riven with Q's/w cant chase fiora with q's cant chase udyr with E, gets fked by sejuani's, sion, galio, annie, azir, annivia, zac's, rammus etc in team-fights.
If you are losing to Yi, it means you are ignoring one person on enemy team and spamming your cc to some random tank or some shit, and that's on you not on Yi. I can bet any one above gold would ever complain about Yi (apart from the wriggles stacking era).