After doing a large number of manual wishlist edits, a useful feature would be a drop down added either to the card entry arrow flyout and the card actions drop down.

Card Line in deck
Sideboard->One, All
Add to Wishlist->One, Missing
Add to Inventory->One, Missing, All

Card Actions
Remove
Add Missing to Wishlist
Add Missing to Inventory

The algorithm is already being calculated to determine the amount of missing cards so the function would inherit that variable/value on page load and pass that to the Add to [respective list] -> All function as the amount parameter for the card line. The Card actions drop down is a "Import a list of cards" entry that is created in the background and populated by all the cards + amounts that are determined to be missing.[/respective list]