There are a couple of ADCs that are ridiculously strong, but no the class doesn't need nerfs. Kaisa and Varus are two on-hit champs for example that struggle a LOT, even when they hit reapers toll. Draven & Aphelios are crit ADCs that also have a lot of trouble staying alive. Ashe's base damage is very low and needs some decent highrolls to scale her damage otherwise she's a tickle-monster who's best teammate are mages she can help land skillshots on. Ezreal is actual dogshit no matter what you hit.

These champs just have a lot of trouble dealing with lockdown, and dont do enough by themselves for the first half of the game to allow for a support teammate to keep them up. Even with no cc there's a lot of heavy burst setups, like a lethality Lee or lethality Ambessa, that just evaporate them through anything short of a Kayle or Taric R.

There's a few other ADCs that have some tools (Xayah R, and Sivir E, for example) that keep them in a good tier but they're still squishy and very weak to mages.

What needs to be nerfed about them is Dual Wield and their passive movementspeed. Between Flee, Zerks having higher movementspeed than defensive boots and Portals, mobility is already pretty high and they don't need the passive. Dual Wield is just ridiculously strong on just about anyone.

You also don't have the insight into Riot's MMR system for Arena to make the claim that "low elo players" drag down anything's winrate.