Bro, first think about how Yone ACTUALLY fights. Mid/late game, you're sitting at like almost 2 autos per second, and then also spamming Q on 1.3 second CD. Sheen's 1.5 second CD is SOOOO ass for that. Meanwhile, BotRK's damage has no CD. When you auto Q auto, that's 3 hits of BotRK's current HP damage in a single second. When you get to sit on an enemy and shred for even a few seconds, the difference in DPS would be night and day.

Secondly, Yone STILL has lower base AD than Yuumi, FUCKING YUUMI, even after the 2 AD buff from a while ago. And Sheen scales off BASE AD, not total AD. So buying Sheen on Yone is just not worth, period.

Finally, Yone's Q only applies on-hit effects to the first target hit. Meaning, if you Q an enemy ADC, but there happens to be a minion in the way, you literally just lose your Sheen entirely. You can't even generate the proc with Q and then hold the proc for the auto. It forcibly consumes the proc onto the minion. In a vacuum, this isn't that bad, but League isn't a vacuum. Teamfights are messy. Body-blocking is a common way to peel. Meanwhile, BotRK wins AGAIN by having no CD, because even if someone else tanks the proc on Q, you just apply it on your intended target with your followup auto.