With the inclusion of 1 and 2 star covers as rewards for winning pvp matches, the 600 point progression cover seems almost redundant as I have acquired multiple copies of said cover on my way up the rewards ladder more than once.
Here is my suggestion: replace it with a new token. Create a token, call it Iconic or some such name and place it at the 600 point spot. It can guarantee a 3 star or better cover. Think of it as what a heroic token wants to grow up to be.