Swappable Cards in Deckbuilder

It’d be nice to associate a card in the mainboard with one in the side/considering section(s) to make easy swapping possible using a button or menu option. There are a few reasons I’d like this:
1) when using placeholder cards that are intended to be swapped later on
2) making the deck appropriate for different play environments
3) when playtesting, so I can easily revert a change
4) to create a package of budget/bracket alternatives
Deck history can be used to accomplish this, but it’s a bit cumbersome to add a card with the intention of removing it just to maintain the changelog.

There are several other major changes that would effectively accomplish this goal:

• The ability to add notes to cards in the deckbuilder could also approximate this behavior, since I could just put “Budget: Swap for X” as a note on the card.
• Version Handling would allow different forks of the deck for various Brackets, paper vs theory, and other constraints.