Possibly relevant to this discussion is the inclusion of separate decks in-game. I know this has been suggested before, but it is worth emphasis.
Many awesome Anti-FG Rainbows are very slow against t50, Level 5, and Level 3, and simply ineffectual against PvP. Thus, many of us keep Firebolt, Shrieker, or Poison decks in our "All Cards" section. However, we also have multiple farming decks, along with rare weapons, shards, and other cards that we're keeping in our "All Cards" section for later or experimental use.
This makes things disorganized. It would be nice to be able to save multiple decks into your account - say, 2 or 3 decks plus an "All Cards" section. Buying a deck slot can cost a certain amount of Electrum- say, 100-200- and it starts off completely empty, with no cards.
Buying a Mark for this deck slot costs 100 Electrum as per usual, and then you click on cards from your All Cards to fill up the deck. This deck can still only be 30-60 cards large, but it can also have 0 cards in it, in case you inadvertently created a new deck slot.