I find that I sometimes forget terms that I haven't reviewed in a long time, especially in large schedules. The only alternatives are increasing the mastery level requirements (post-poning the issue) or doing the "anything in this schedule" focused review.
It would be very helpful to have a "not studied recently" option under focused review. It would literally be the opposite of "studied recently"; if I haven't reviewed a term in X days or more, include it in that focused review.
You could try altering the amount of days for iterations between reviews.
You can go into each individual schedule and under advanced settings, edit these values. It may help a bit.
That feature does sound nice though! There would have to be a set amount of days since you last reviewed a term as the cutoff point, I suppose? What would the selections be like? (I.e. last 30 days, last 7 days on existing ones)
Oh, I forgot to mention. There is one flaw with this request, though. By taking some of the oldest terms that are not up for review, and reviewing them, you're dooming them to a much longer time at that mastery level. Focused review can almost never raise a mastery level, as that can only happen if the terms are ready to be reviewed.
So if you have a term that, for example, is set to be reviewed in 10 days (but was last studied 60 days ago), studying it via this new option would a)not raise the mastery level and b)start the timer back at 70 days.
