I have been using the review page for "All My Stories" with a sort of Last Edited to review cards that I previously marked as learned and then tested.  While the last edited sort is usually in order of last learned, as some cards drop out of memory, this workaround isn't perfect.  It would be nice to add a Most Recently Failed sort to this list.  I don't know if you store the date and time along with the count when you fail a card, but if it is, that would allow you to build a list that bubbles up what you most recently had trouble with.

A suggestion...