I much prefer game jams that have a large number of participants as it tends to make the experience more exciting as well as increases motivation. Plus jams with a high number of people joined tends to mean that the jam is properly planned and makes sense (as people don't tend to join jams with silly themes or ridiculous rules).
Instead of only the default sorting (which is by whatever is the closest to finishing), I think an ability to sort all the jams by the raw number of people joined would be useful as it would eliminate needing to scroll and comparing numbers.
Edit: Well I just noticed a similar request on the second page for sorting by submissions and saw the admin response. I'll leave this topic open just to express my desires as well but if it seems redundant, please feel free to just delete it and forget I said anything.