Huge issue with executioners calling and the grievous wounds revert.

Lets look at how many champions have the ability to heal allies.

Sona, Nami - They will just go back to being irrelevant due to how weak their heals will be with a Runaan's Caitlyn, Sivir Ricochet, etc. applying the healing debuff to your entire team.

Soraka - This is really the only champion that has been problematic due to the grievous wounds change. Don't destroy the 2 champions above because of it. She will have the same problems as Sona and Nami if this change goes through. Needs a rework from the ground up.

Janna, Taric - You can argue the change made them too strong but it can easily be fixed with slight tweeks/nerfs.

Kayle, Bard - Their heals are mainly for the move speed boost and are normally maxed last anyway so nothing really will change.

Nidalee - I assume it will hurt her but not enough to kill her. I'm not sure how she will be after the mid year mage update so its hard to say anything about her.

Alistar - His heal is meh. Not a big part of his kit.

Fiora, Kindred - Seems like a huge nerf to their team fighting for the same reason as Sona,Nami and Soraka.

Riot even said the point of the change was to let healers do their job so either don't change it, remove executioners calling or heavily nerf it. Executioners calling should build into something that you have to go out of your way to build opposed to something that's common in every ad champions build (last whisper.)