> this would allow me to express object "knockback" (like a character getting knocked slightely backwards when hit by an object without using sloppy physics...)
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That would require some new conditions to be added to the platform behavior. Something like "Object is pushed away" with a dropdown for "From left," "From top," etc.
I think if this method of pushing platform objects away from solids rather than up through solids is implemented, I think "Object is trapped" -> "Horiz," "Vert" would be a useful condition to have. Like it's intersecting on both the left and right and can't be pushed either way. You could make squishing traps and stuff that way.
How about "Acts as physics object" with a variable that determines the force it can exert and can be exerted on it before it gets pushed away? Also, "Destroy if clips object" option for squishing.