I would not say we think Grievous Wounds is in an optimal state - we do want to revisit the system. In the meantime, we're going to change Dr. Mundo and Soraka to smooth them out a bit given the counter items available. The goal is to increase performance when GW is applied to them, and slightly reduce it otherwise.
A fair amount of champions invest heavily in healing; these two, more than others, are entirely built around healing as the output they actually offer. This is contrast to say, Aatrox, Vladimir, or Swain, who definitely care about healing but have a lot of healing-independent offensive outputs to give their team.
Soraka
Astral Infusion (W)
Heal :: 100/135/170/205/240 >>> 100/130/160/190/220
Wish (R)
[NEW] Clears Grievous Wounds on Allies before applying the Heal.
Dr. Mundo
Maximum Dosage (R )
Heals 20% of missing HP >>> Gains 15/20/25% of missing HP as Bonus HP
Heals 20/45/70% of max HP over 10s >>> heals 20/40/60% of max HP over 10s