I think there should be a daily login reward system like in some other games:
Day 1: 100 Clintz
Day 2: 1 Credit
Day 3: Common Card
Day 4: 500 Clintz
Day 5: 5 Credits
Day 6: 1000 Clintz
Day 7: 20 Credits
I wouldn't mind a free card pack or 2. Maybe base it off of how long a player has been on this site; like a veteran reward. I'm coming up to my 4th year since being here.