The difficulty with fixing damage creep

One of the problems that league has right now is that the overall damage level is too high, which leaves people who play tanks with a sour taste in their mouth. Now we can all agree that something needs to be done, the solution that a lot of people are suggesting however is a little flawed though. What people suggest Riot does is cut damage by 20% or so all across the board, but the problem with that is the fact that not every champ will be affected by that in the same way. Damage champs who's only gimmick is a high damage output, or excellent play potential, will become literall trash if their damage is cut. They have a very "knifes edge" sort of balance, any form of nerf can hit them harder than you would expect. My evidence, the Vayne nerf of 5.20, a mere 3 ad taken off, but we can agree that it did drop her much more than we expected.

So basically this whole post is meant to say, damage is high, and it isn't an easy fix.