I think your suggestion would have the unintended side effect of having Moira’s deliberately expend Biotic energy in order to do more damage.
I could imagine a lot of games where Moira is simply throwing healing into thin air in order to start the fight with more DPS in the hopes that by doing DPS from the start she will have enough resource to heal.
It also punishes good Moira players for managing their resource well, if a highly skill Moira player wishes to use exactly the amount of Biotic energy required to heal their DPS is being punished for skillful management.
Please check out this suggestion for Moira changes to her Biotic grasp, just like yourself it’s a suggestion aimed at tackling how Moira plays rather than her actual balance but I’ve approached it slightly differently. The more feedback we get on these types of posts the more likely it becomes and issue that gets addressed, in one form or another.