How to fix bruiser-style gameplay on non-bruiser champions (Yasuo example inside)

The main reason why these builds are so successful is due to how Fervor of Battle works. A flat on-hit damage increase that stacks means that your AAs are going be doing the equivalent of 111+ AD (roughly 2 items worth) of damage at 8 stacks (at lvl 18). This means that you can replace 2 slots with defensive items without losing damage on your AAs.

This can be resolved by making Fervor of Battle scale with bonus AD/Total AP instead. By doing so it rewards people who build more damaging items whilst not tacking on free base damage. Generally speaking, AA-reliant adcs build roughly 145-170 bonus AD (IE+BT/MS with the occasional BotRK) so a stacking 8.75% bonus AD on-hit (at lvl 18) will give about the same damage (or more if you don't buy a defensive item) as before to ADCs mid-late game, but less damage in the early game where base damage is king. Bruiser yasuo builds usually 125 AD (IE+FM+BotRK) so it will do less damage on him late game (by punishing his lack of damage items) and make his early game less oppressive (since he builds low AD items like FM/Botrk first unless he's ahead).

If even the scaling on Fervor of Battle isn't enough to dissuade people from building bruiser yasuo. The is another solution that can be used: Simultaneously Nerf and buff his passive by Lowering the bonus crit from x2.0 to x1.25 (from 2 items (50%) max crit to 3 items (80%) max crit) and buffing the damage done by his crits by removing the -10% nerf (and possibly adding 10%-25% to make up for loss of AD he would have built on his normal 2 crit item build) That was he is forced to build at least 3 pure-damage items before going tanky (which means he'll have either lower defenses or lower HP).

If both are used, it will reward Non-Bruiser yasuo builds by having them keep their damage at the same (or slightly higher) level while bruiser yasuo builds will consequentially do much less damage as a tradeoff for being tanky. (as it should be)