I completely agree and have tried so set up some small group meetings—you can have up to 24 people in one 1:1 meeting on swapcard. This works especially well if you create a 1:1 with one person and then add others rather than immediately creating one with 24 people because the latter does not show you whether invitees are actually free at the planned time while the former does.
On the organiser side, it might be cool to move the cause area/work specific meetups earlier in the conference.
I appreaciate how many recent/contemporary thinkers are included!