OK, my entry is finished and available at http://www.gwern.net/Spaced%20repetition#literature-review

(I chose to stick it on my site rather than in a LW Discussion or Article because I think it makes more sense in a context, and because I really hate the edit box on LW - I probably would cut my wrists trying to get the footnotes to work. You may need to force-refresh if you have been there before).

I believe I hit all the points requested except for the research questions - nothing obvious occurred to me that the researchers missed, and there's so much research I'm not sure what they consider really important besides the fixed vs expanding question, which as I explain, is not of much interest to us practical folks.