Vayne's Silver bolt is not her main problem.

Her Q scale 50% AD and have a 2 second coodown. And it cancel all auto attack toward her if there was no pick ward. Basically, she is a mini , and none of them can do their job better than , no other ADC or Assasin can solo or assasinate her (well, according to hi im gosu senpai, only can) cuz if there are no pick ward, you cant auto attack her. I love how she can be invisible, but, please give her a weak spot.

12% max HP is not the problem it would deal less damage if you have less health, if you have 2000 heal it would deal 240 true damage, the old system deal 60+160 = 220 true damage. Let me prove this is a nerf to vayne toward other ADC: Let count how much health you should have to consider vayne's W next change is a nerf 8%x + 60 = 12%x => x = 1500 You have to have less than 1500 health if you want the new system deal less damage than old system. (12% of 1500 is 180, 60 + 8% of 1500 is 180) So let check wiki list of champion's health at lv 18 too see which one got less than 1500 health and we clear :) http://leagueoflegends.wikia.com/wiki/List_of_champions'_health