Why has Vayne’s W been so damage crept over the years?

5.22

BASE TRUE DAMAGE [20/30/40/50/60] ⇒ 0

TRUE DAMAGE : [4/5/6/7/8% of target's maximum health] ⇒ 6/7.5/9/10.5/12% of target's maximum health MINIMUM DAMAGE 40/60/80/100/120

7.19

PERCENT HEALTH DAMAGE : [6/7.5/9/10.5/12%] ⇒ 4/6/8/10/12% target’s maximum health

MINIMUM DAMAGE : [40/60/80/100/120] ⇒ 50/65/80/95/110

8.14

MAXIMUM HEALTH DAMAGE : [4/6/8/10/12%] ⇒ 4/6.5/9/11.5/14% target's maximum health

It’s pretty absurd to see where this champion started to where she is now in terms of %health true damage which is by far such a unhealthy mechanic.

What’s next 6/8/10/12/16%? You took a late game carry and made her into a mid game champion after two items.