Yeah that sounds very similiar to what I've done actually. I thought what Chiyu did with Extra really spiced up the early-mid game, which was something I enjoyed alot. Avain did a great job with the late game, so I really didn't mess with that. What you said sounds really awesome too RPG, I'd definitely play your mod if you put it out.
Just a heads up. The DCM component works fine with my mod but Revolutions(Barb Civ, Tech Difusion, Revolutions) does not for some reason. You can play the game with those options on, but you will crash around the renaiissance/early industrial. I'd figure this out but I lack the skill in XML(I've only been doing XML since June). Also Rev has an upper limit of 50 civs, and that number is exceeded in the mod. I believe the Revolution mod has a problem with modular-based civilizations, as the Rise of Mankind mod's megaciv pack had the same problem(added lots of Modular civilizations).
Many of the new civs I added have unique art. The version I'm working on actually has unique unit art for
Phoenicians
Berbers
Israel
Arawak
India(Hindi)
India(Chola)
India(Mughal)
Vietnam
Iroquois
Romania
Nubia
Assyria
Hittites
Just to name a few. I have redone the techtree(alittle) as well.