It occurs to me that there's another situation in which hand-matching is likely to be a plus feature: a small exchange (which certainly describes fkficfest).

You may recall the situation we both found ourselves in for rarelywritten, where we could pretty well predict who we were likely to find ourselves writing for, at least within a couple of names. When there are a lot of possibilities and a relatively small number of players, one can find oneself with very few matches.

Well, I've just signed up for fic_corner, in which the AO3 computer has paired me with someone I've been matched with more than once before. I made sure to offer more widely, of course; but the algorithm has no way of knowing what my previous matches have been, especially since they were in other exchanges.

Furthermore, three of my requests weren't offered, and (unless I'm mistaken) the other two were only offered by one person. To be precise, the same person whose story I am writing. In other words, I have a horrid suspicion that we're going to be swapping stories. Maybe even in the same fandom. Computers are a bit dumb that way. (Well, either that or she matched with someone else and I went out to pinch-hit.)

I suspect that fic_corner is a bit large for hand matching. However, I know that, in modding fkficfest, you make an effort to ensure that people don't keep getting the same writer or the same recipient. Given that FK is a small fandom, I can quite see potential players liking the idea that you hand-match prompts.