What is bad about combat healing being nerfed is that it completely obliterates any chances of peeling when you get attacked and enabling your teammates in combat.
It puts the support into a position where if they get attacked, they cannot even help each other out besides killing the enemy (gl trying to do that) and in combat, their only valuable assets will be utility and damage, not actually healing their team during combat to sustain them.
Which in essence, just makes them out of combat medkits. They might as well become worse dps for the duration of combat. Support is the role in the game which main job is to provide sustain for your teammates and characters like Symm got a role swap because they were unable to provide heals for teammates.
If support is unable to perform their main duty when they’re actively supposed to play the game, well… You’re punished for playing the game and the support role.