Buff Cut down rune
As of right now coup de grace is just leagues above cut down. I don't know anyone is who takes this rune because it does not have good stats this is what it currently is:
PASSIVE: Deal 4% bonus damage to champions with at least 150 more maximum health than you. This increases up to 10% bonus damage versus targets with 2000 more maximum health than you.
If they you make it to late game (as rare as that is) and they dont have over 4k health with how it stands you are just dealing 4% extra damage. with a standard ADC crit build (
) its about 10 extra damage per hit on a tank.
idk how to change it to make it work but maybe lower the second half max health from 2000 to (1000-1500) this way it only applies to tanks since even if a mid runs Rod of ages it wont get the 10% attack bonus for ADC.
