One thing I've curious to see when EU:R comes out is if there are mechanisms in place by which technology can move in a retrograde direction, either built in or script enabled. Antiquity is filled with examples of cultures that established flourishing and technical civilizations only to have barbarians knock them back down to pre-literate, pastoral societies. When the Saxons pushed the Romano-British remnants to the Welsh hinterlands, the Romano-British didn't manage to retain stone working, tile making, wheel spun pottery, or legionary tactics, equipment, and organization. Acquiring technology costs money & resources, but so does the maintenance of technology. It'll be interesting to see if the folks at Paradox put some hooks in so we can mod more than just the revolts and invasions into a fall of Rome mod.