Harmony - Troop Symmetry

Could you tell me what motivated this choice?

People are known for their skill.
(This is probably their strong point in all games, and it really reflects their abilities.)

Added 3 minutes later

I'm thinking about how to strengthen the guardian angel.

"Resurrection" is a skill for angels, not for the human faction.
Not only will it look absurd for humans, but you'll also ruin the atmosphere of the "angels."

It might be a good additional ability for the "seraphim" unit.