All the other points make a lot of sense to me, but something about deciding on topics and sticking to these sounds a bit over engineered to me. I've never taken part in such a setting so maybe I just don't get it yet, but it seems very limiting.
find it works best when the conversation is less outward ("how would you solve healthcare in America?") and more inward ("how do you stay motivated when it feels like everything is working against you?") where each person's personal experience and sharing doesn't have to be directly relevant to you, but you can interpret your own thoughts/feelings/experiences through a different lens.
Yeah, that's how it strike me, too. I suppose it depends on the purpose of the conversation. If it's for enjoyment, constraining it to a single topic sounds awful. Most of the joy of good conversation is in how it rambles across topics according to the mood of the participants and serendipity.
But if it's a focus group of some sort, then limiting to a single topic is desirable.
It's a bit like dancing with someone in that respect. You have to be ready to alter your moves so that you can stay in sync with your partner. The magic is in the coordination.
(Then again, I can't dance well either, so maybe I have some Generalized Pace-Keeping Disorder; is that a thing in DSM-5?)