FrogReaver
The most respectful and polite poster ever
By distinguishing special actions from regular actions, per what I posted.
Regular actions = anything under the "Actions in Combat" section of the rules.
Special action = pretty much anything which currently uses a bonus action. Special actions will let you do something in addition to taking a regular action (sometimes limited to a specific one, like Attack.)
Healing Word would in this revision be a swift spell. Casting a swift spell is a special action. Per the text I proposed, you could cast healing word, and then you can cast a cantrip, or take any other regular action (i.e., not another spell, and not Second Wind, or Bardic Inspiration, which would both be Special actions.)
Maybe a better wording of Swift spell would be like this:
Casting a Swift spell
Special action. When you use the Cast a Spell regular action for a spell with the swift property, you may also take any other regular action. If you choose the Cast a Spell action again, you are limited to casting cantrips without the swift property.
So what you have is a system that is functionally equivalent to bonus actions?