I think Overgrowth’s damage was fine in a vacuum. It was the fact that you could throw it down and then just run off that made it a problem, since that was basically guaranteed value – enemy players had to choose between chasing you or killing the pot, and either way you were getting damage done. No skill, no real counterplay.
I think if you can’t just run away and have the Overgrowth do the work for you, it would be fine to bring back its damage, or at the very least add an armor reduction effect to make the Terror hit affected structures harder.
I want the Terror and its Overgrowth synergizing with each other.