That could get a bit messy with the random mission availability system, it would take away even more player agency if you get locked out of a portion of the already limited list of available quests because they haven’t come up on the mission board at a lower difficulty before.
I’m specifically referring to the jump from Heresy to Damnation, that still leaves everything from Heresy downward for finding quest missions. I don’t think it would limit much at all, since theres never more than 2 Damnation missions on the board.
Having thought about it, you probably mean finding each mission in order to unlock Damnation. I’d easily circumvent that issue by making it mission type; so Espionage, Investigation, Strike etc,(just like the penance,) that way you’re not looking for a specific map, just each mission type.