I agree on this, clone chamb, donations + crates etc brings enough cards, I can upgrade most of my deck now if I want to, however, coins are the problem now. Leveling to level 10 costs 4000X3. That's 12000. Just for 1 unit.
I have now got enough cards to level up, from 9 to 10, flame/chocks, missile/laser, avatar/mammoth, basically all commons, generals, handful of epic cards.
But with only having around 24K gold I can only upgrade 2 units. Rest stays at 8-9...
I wish I could burn unwanted cards for coins or something. I have over 1000 cards for riflemen, venom and drones. I will never upgrade these units, I would more then gladly burn these cards for extra gold.
This is what I agree with the most! I have excess cards across different units, and most of them are level 7, with few being at 5 or 6. I would want to sell all those excess cards to upgrade them all to level 8 or something.
If you managed to sell all your excess cards and earned even a portion of the funds, it will be more than enough to upgrade your entire GDI and Nod army from level x to level x + 1, if not x + 0.33 or so,