Pardoning Trump would continue the example set by Gerald Ford in pardoning Nixon.
"Helping the country heal" seems hollow to me. To use a few metaphors:
1. Physical healing can't properly happen until the foreign object is cleared and infection removed from the body.
2. Mental healing doesn't fully happen until person comes to terms with what's happened. Burying the trauma is a risky time-bomb of a "solution".
If injustice goes unpunished or unaddressed, victims typically don't have closure. They lose confidence in the rule of law. Some take it into their own hands.
Large portions of the American public have been traumatized by Trump's behavior. We are seeking justice.
And any temporary comfort from pardoning Trump would be undermined by the uneven application of justice.