unless you have a party full of healers, Healing does not compete with one Scorching ray, it competes with every other thing that you can throw at the party per round,
there is loads of "auto-attacks", rage, sneak attack bonuses, alchemical items and what not.
Point of buffing the spell is to make it worth the slot it is spent on.
And as most people find healing as boring, it is moved to Bonus action so your Action stays free to do something not boring, and as it is a spell you are still limited to Cantrip only spells as your action. Or to whack someone over the head with a mace.
Healing word is now loved/hated because it heals pitiful amount of damage, but still removed dying condition and those pesky failed death saves in one Bonus action.