This is suuuuch an easy benefit to implement, has no cost to AC, and would would make many happy customers. I don't see any obstacle/difficulty/downside for AC in implementing this.

EDIT: after thinking it through for over 5 seconds, it could get a little messy. At what point can seatblocks be 'overridden'? Obviously if there's more pax than free seats available. But what about a couple travelling together, and due to a bunch of middle seats being blocked there are only singles left. Should it be overridden in that situation? And there's a hundred more examples. IMO it's hard to draw the line for when non-status customers have to choose between available seats, and when the seatblock should be overridden.