I wanted to respond and let everyone know about my plans for this. There were a TON of ideas in here. A lot of them were, unfortunately, either beyond the scope of what the focused review system is meant to express, or would add so much complexity to the FR panel that it would turn it into a huge list of options.
So, I am working on adding a focused set of additions/expansions/changes that I feel stick to the current format closely enough that they'll be adopted easily.
As I have not yet begun on these, I welcome any further comments on the below contents:
Officially planned (in no specific order)
1. Allowing a FR to select more than one list
2. Most missed (most likely with a few options: missed most times, highest missed percentage)
3. Highest Mastery (At this point, I do not think I'll be adding a way to do mastery ranges)
4. Expand vector selection to allow all vectors, including ones not in that schedule.
5. Reviewed least recently
6. Exclusion options
Ex. Choose terms to exclude: (Studied recently (same options as above), Learned recently)
(Note: the system does not note which terms are studied in a regular quiz, and which ones are in a FR, so there is not a way to do "batches" like several of you requested. The "exclude terms reviewed today" will get you pretty close, though.
7. (This may be a five minute job, may be several hours - need to look into it more) Option for FR not affecting mastery.
---> With this one, I have not yet decided if it should not affect them at all, or if it should not push reviews back, but allow terms to fall (or give this as an option)
Unfortunately, having focused reviews expand beyond a single schedule is currently not in the scope of this. I do hope to add this, though, but it would have to have a place somewhere on the dashboard that is "above" all the reviews. Wording to be finalized later, but maybe a "Global focused review" (you'd have to choose a type: words, kanji, etc.), with the same options as the normal focused review. From a technical standpoint, I think it's definitely doable. I'll happily take mockups of where you think it would go on the dashboard.