Adding the "solo" option in game search and advertising?
I think that would require the Game Info section to have a spot where the GM specifies how many players they want. Which would require rearranging that page, and adding more interface bits. Then a column would have to be added to the Players Wanted grid, plus expanding the search page.
Not sure how much of this would actually constitute work on jase's part, but off the top of my head it would require all that at minimum.