As noted, the highest authority mentioned in Divine Divinity was the Duke of Ferol, who had a sizeable castle. Aleroth was a little village that took care of itself and there was apparently a merchant class mixed with nobility who ran things in Verdistis.
All that went to hell after Divine Divinity: as far as I can tell, The Divine One (being the incarnation of the Seven Gods - who aren't mentioned EVEN ONCE in Divinity II) set up his Divine Order and became the law and religion of the land. And after his death the Order persisted and you had the various factions rise to power like the Seekers and the Slayers. The old nobility of Ferol and Rivertown seems all but forgotten.
There were also formerly churches and priests in Rivellon - the religion was mainly founded on the Seven Gods, and the fulfillment of an ancient prophecy of Reuben Ferol, who prophecied that he would be reincarnated when the Black Ring and Lord of Chaos rose to power again. This prophecy was fulfilled in Divine Divinity by your player character, so the Divine Order became both the new religion and the new law. So, in a way, you are right to wonder why the in-game history and lore of Divinity II seems to be shallow - but the reason is that so much of was rendered obsolete by the recent wars - the current state of affairs is pretty much all there is to see - various 'orders' all sort of bumping elbows trying to maintain power and prosperity.
Thanks! I'm beginning to put the pieces together here.
Is there a formal tenet of the church of the Divine Order, such as rules of conduct, or commandments? Do they have the promise of an afterlife, with a background threat of eternal damnation? (There is evidently a Hall of Echoes, but what else do they have?)
The idea of an old, sidelined nobility and/or priesthood is intriguing. It would open possibilities of a manysided powerstruggle beetween the old and the new, now that the Divine is out of commission.