Card Totals and Storage Suggestion

So, I've been bouncing some ideas around about card totals and what to do about it.
We all want more space to store cards.
PM says that more slots will cause performance issues.
Why not allow players to "store" cards (ie. make them inactive and take them out of the list). Put them in a collector's box (to use a guildie's word for it). This puts less demand on the system because fewer cards have to be constantly shown, sorted, and processed! This might then allow for additional card slots later. Keep in mind that the stored cards would still count against the total allotment. For example, if a person has a max capacity of 350 cards and really only ever uses 50 of them (7 teams on mobile * 5 cards = 35 card, + 15 to rotate in regularly), and if they had 100 jewel dragons on hand then they could store the other 200 cards. This then leaves only 150 "active"... and you could have a 2nd box for the jewel dragons... this would still count against the total, but they wouldn't need to be displayed all the time (only when strengthening). If the 2nd option (the 2-box one) is taken then the system really only has to track the 50 active cards.
We all want more space to store cards.
PM says that more slots will cause performance issues.
Why not allow players to "store" cards (ie. make them inactive and take them out of the list). Put them in a collector's box (to use a guildie's word for it). This puts less demand on the system because fewer cards have to be constantly shown, sorted, and processed! This might then allow for additional card slots later. Keep in mind that the stored cards would still count against the total allotment. For example, if a person has a max capacity of 350 cards and really only ever uses 50 of them (7 teams on mobile * 5 cards = 35 card, + 15 to rotate in regularly), and if they had 100 jewel dragons on hand then they could store the other 200 cards. This then leaves only 150 "active"... and you could have a 2nd box for the jewel dragons... this would still count against the total, but they wouldn't need to be displayed all the time (only when strengthening). If the 2nd option (the 2-box one) is taken then the system really only has to track the 50 active cards.