I thought it was mentioned in a dev diary that a new nation of Sauromatia replaces Pythium in Early era.
Oh, I think it was also mentioned when one of the devs answered a
"What's your favourite nation?" thread.
That was evil, EVIL I say. It's a good thing they are so good at making games that we don't care.
Besides that, I think you already answered those question. Of course, if you are fond of their combination of mages, those kind of combinations might be found in other nations. Access to easy Communion, good Astral and some Elemental magic shouldn't be that hard to come by.