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 based reward like usual 30 minutes a day. With 1 stored extra play time daily (if you didn't finish yesterday) and reductions for missed play time.
(adjust it with a weekly timer subtraction, subtracts 5 minutes from the daily if you didn't play yesterday
10 minutes if you haven't played in 2 days, and stores up to 30 minutes of *daily consecutive reductions*?
e.g. -10 min to the timer, for 3 days in a row, if you havent played for a week!)
Essentially this idea basically means, if you didn't complete your 30min daily for w/e reason, you get a 25 or a 20 minute daily! Also being able to hold over 2, 30 minute dailies isn't a bad idea either, if I don't play for several days because of a busy week it'd be nice to see 2, 20 minute dailies on the weekend for at least a decent reward. Or 2 dailies (for a total of 55 minutes) if I didn't play yesterday. This concept's basis is to consider that players who do play daily, will guarantee an advantage, 14.2% per day of a total weekly payout for daily players. Backstocking a missed daily through a week at least provides almost 30% of the total possible weekly reward.
Daily quests (either PVP or Coops, no forced PVP or PVE)
Those daily types should probably just be 'any campaign, PVE 6 or harder, or PVP quest', maybe 2x per day? (1 Solo or multiplayer, 1 multiplayer required?)
Quest completion counter (keeps a running tally of all these quests you've completed, providing bonus packs at specific intervals)
Already a standard, and not a bad idea, it works fantastic as an overall progress condition, maybe gets a bit steep when your far in though.
Proposed Suggestion: Another secondary running tally counter, like the completion counter, every 10 missions (PVE6, Campaign, or PVP)
that you complete, rewards you with a singular common card from a unique (custom commons only) booster set.
By offering 1 free common for the completion of every 10 missions (not quests, but any mission meeting the same requirements) common cards will have low prices by ensuring the common cards are just that, common. This suggestion revolves around several ideas, ease for new players to purchase common units and spell cards they'll need reducing any shortages, players that continue playing after completing the dailies have a basic incentive to continue enjoying the game, even if its not huge or highly profitable. This suggestion also avoids providing an additional BFP directly to players who play for too long causing any large negative impact on BFP production.
Don't figure I mean to tell you how to make or balance the game, I'm just happy to see and play it again, just thought this one through for awhile and figured I'd offer the ideas, even they don't get implemented. Thanks for letting us enjoy this classic again.