Just provide them better base stats to defense/offense and some durability on items that wont allow bruisers to also abuse. Honestly the "crit meta" was silly as being hit by 1000+ crits is terrible design as well. So a smoother dmg curve to ADC is very good direction to go, however they have been balanced around the old crit system and the "glass cannon" concept which really just isnt fun or balanced design once you remove the cannon part.
As an ADC if I am ahead of jax lets say he shouldnt be following me around the map hoping to catch me out knowing he will 100% kill me. This isnt rock paper scissors the problem with ADC atm is they are such a free kill since they get ZERO defense (no adc items really have any defensive stats) usually very poor kits (next to no CC and terrible scaling) and now that their dmg has been toned down they just cant compete. Everyone aims for the ADc now not because they are big dmg, but more they are instantly killed.
So just stay the course you brought their dmg down, but then they need some defense. Im not even asking to be able to beat irelia 1 v 1 when we are equal level and items I am asking that I can kill her 1 v 1 when IM AHEAD 1 item. As it is now Im am pretty sure irelia with a tri force will destroy an adc with 3 items lol, LIKE DESTROY not even close. Or if we catch irelia out 3v1 she will still dirt nap the adc before the 3 can kill her. BTW its not just irelia she is just an example.