This is an interesting thread. My wife has mentioned an interest in 'family style'. Even without the love/sex aspect I have had long created a Tribe that loosely self identifies as a unit, akin to a family network (think cousins and uncles that live separately but get together regularly).
I'm not sure she wants a large family, either, since she has only mentioned 2 husbands and 2 wives.
I think there's another aspect to the conversation about family vs hub; There are actually different family styles, too! At least as I've seen it there are 'democratic' families where there are a bunch of equals and those not equal are being trained to be so, and there are 'hierarchical' families where you have the alphas, the betas, and then the younglings, and the younglings either grow into betas or leave and start their own families, with only a loose connection.
So that, I think, also applies to poly families, or rather, there is a spectrum of behaviors between those two, with a very light hierarchy in the more democratic groups and ver tight hierarchy in the less democratic groups.
My tribe was very democratic, but my brother and I ran it as benevolent dictators because no one else in the group was interested in organizing events or activities. In other words, we kept the tribe together and organized, but let the members actually do what they wished as they wished it.
You might even be able to fit hub into that model where you have the spoke connecting different families. In other words, my brother and I were both a tight real family group, but we were actually hubs for a much looser family group.