replication inter-sites, rep. partner

I manage a network with 16 offices total. Each office has only one DC except the HQ that has 2 Checking the connection in sites and services i found out that most of the DC (10) have the same 3 replication partners, 1 site have only one partner and those 3 DC have connections with almost any DC of those 16 sites.
By replication partner i mean connection objects in the NTDS site object.
My question is, is it normal that almost every DC is partner with those 3? what does it means? The DC that only have one connection or replication partner, is it going to be in “worst shape”? When changes happen should i expect more traffic with those 3 DC? is this configuration fine in general? You can see a graphic in www.rezuma.com/ut

Thanks