I have to disagree.
There needs to be an item that allows everyone to fight tanks (or tanks will be broken) - however it must also be a niche item that serves very little purpose outside of fighting tanks.
And yes, this botrk will be better at fighting tanks (a bit), however it's an absolute garbage for fighting assassins, mages, other adcs and some of the fighters. This way this item will be picked only if you wish to counter tanks, and you will pay for it with reduced effectivness on more squishy targets.
Now I will show you some numbers (I like numbers) to present what I mean. We will be looking at 4 different scenarios - Ashe vs tank with current LW and Botrk, Ashe vs Squishy with current LW and Botrk, Ashe vs Tank with my proposed LW and Botrk, Ashe vs Squishy with my proposed LW and Botrk.
Ashe with IE, PD, Botrk, LW and Berserker Greaves (let's assume 6th item is a defensive one and doesn't matter at all), stanard 21 offense masteries and runes
AD: 276,4
AS: 1,90
Crit Chance: 55%
Armor Penetration: 39% (LW + Devastating Strikes)
Vayne - as squishy target
Health: 1909
Armor: 77 + 11 bonus = 88
Zac - as tank target
Health: 2229 + 2150 bonus = 4379
Armor: 83 + 201 bonus = 284
**With current LW and Botrk:
**
Against Vayne -
Average damage (look below) per second: 716,2 damage
Volley (W): 232 damage
Time to kill with AA: 2,67 s
Against Zac -
Average damage per second: 471,3 damage
Volley (W): 130 damage
Time to kill with AA: 9,3 s
With my proposed LW and Botrk:
Against Vayne -
Average damage per second: 541 damage
Volley (W): 194 damage
Time to kill with AA: 3,53 s
Against Zac -
Average damage per second: 485,2 damage
Volley (W): 116 damage
Time to kill with AA: 9,03 s
Average damage includes critical chance and damage multiplier from IE as well as Botrk damage applied with half of maximum effectivness (which is in fact the average damage the botrk deals).
So, if you look at those numbers you will see that tanks remain largely unaffected by the change (the botrk hits more but the LW penetrates less). However - it now takes 33% more time to kill a squishy for the Ashe, which is a huge difference. This is a straight up buff for tanks.
All of this is to add choice in the itemization. Right now Botrk and LW are the best choices, no matter if you are up against Tank or a squishy. I want them to remain as a best choice against a tank, but I also want them to be a subpar choice against squishies. Thanks to this an ADC will have to think "Is their tank a threat to build against him or should I just build straight damage to kill their APC/ADC/etc faster?".
Anyway, I hope you got what I meant to say (English is not my first language, so I sometimes struggle to explain something).
Disclaimer - the builds posted for Zac and Ashe (mostly due to the fact that neither have any defensive or offensive steroids) are purely for math purposes, not for viability.