HP/Anti HP AD Balance
All of these items give considerable HP in the mid-late game to every class other than ADC (I'm excluding items that give only armor):

Let's see our true anti-HP options:

Notice a problem yet??
And no. Not every ADC can build lethality items or Black Cleaver. And I'm not even talking about armor shredding, I'm talking about how so many things just give out HP.