If they keep the established rotation pattern of the latest twelve, the next progression covers could look like this:Winter Soldier - blueGamora - redCoulson - purple (?)New character (Yondu?)Now, after the new guy we should reach Sandman in the T12A list, but I don't think he will be a progression reward so soon. So it's more likely that the list starts back at Agent Venom.
The devs probably read this thread and then alter their plans just to mess with you.
I need any colour but red for Gamora, so I hope that prediction's wrong. I just had to roster the two red covers withering in my queue.