Tried thinking about this one tons, since you've brought the game back, and will say again, thank you for reviving this gem of a game.
It won't bother me how the progression system turns out either way, I can enjoy solo or coops with the basic starter cards we get: giant thanks for the mostly solid starter set.
As long as progression is at least as good as it is now, the game is completely playable and doesn't damage its long term value. Just tossing a few instance based idea suggestions!
MMOs have a 'Rested bonus'! Shouldn't be hard to do something similar.
Daily: Play time base