I think Mobage could learn something from this. A lot of the fun of card collecting games is having cards or archiving cards that other people don't have. When I look at Empusa for example, she was just a high normal card with titillating artwork, but sells for quite a bit because she was discontinued ages ago.
I feel that Mobage should start reducing some of the older High Rares and SRs from Rage of Bahamut card packs. I think it would be a good idea to remove cards like Great Spirit, Elaine, Lovely Elf, Master Witch, etc. These cards don't really work in any decks anymore and only really serve as cards to increase somebodies archive. By removing them and adding extra perks for Archive Rage of Bahamut would be giving players something extra to do that's fun.
If Rage of Bahamut started discontinuing cards while adding effects to perks like you get 5 extra points to distribute every 20 Archives (after you cap your card inventory), I think we'd see a lot of active trading which would pump a little more life into the game. It would also help people sitting on tons of 1HP HR cards liquidate them.
The final effect of a change like this would be that a lot of the 1HP HR cards are removed from card packs. This would increase paying customers ability to get better cards, increasing their desire to purchase card packs, because lets be honest, right now even if you get an SR there's a 70% chance you get an SR that nobody wants because it's inferior to newer ones.
These were the thoughts I had when more new cards were released. What do you think about the constant releases of new cards while the old cards remain on the market?