Right now it looks like the following:
-Information is more quickly accessable
-Somewhat improved graphics
-Few more nations
-Few more spells, rituals and times
-Few more "improvements" (features)
-Balancing
-Little less micromanagement
But still I don't feel any big steps have been taken, or at least they haven't been revealed. Two new "features" I am confused about "Luck" and "Magic Battles" as a "choice" in one turn. Second bullet here:
http://www.shrapnelgames.com/Illwinter/Dom3/2.htm
I would consider a big step to be something like having random events generated based on what is hapenning in the game. Another big step would be a highly improved battle organization system such as giving certain commands or supressing certain actions, and just more commands in general. I will say that national summons is one big step. Oh, and I just remembered the other big step I wanted: Non-magic-based recruitable units actually being useful. Oh yeah, and how about the ability to recruit seige vehicles? catapults, etc.
Now, I knew as soon as Dom3 was announced C'tis would be getting calvary units. I thought they would be lizardmen on the lizard-dood's back, but they are in chariot style. Good enough for me.
Oh yeah, the game cover looks like crap.
And the in-game UI didn't change much (besides the extra information everywhere)
"Fifty different playable nations. Some of the new nations include Ermor, New Faith, based on the early Republic of Rome. Marverni, inspired by Gallic tribes. Kailasa, Rise of the Ape Kings, inspired from Indian and Hindu mythology. Jomon, Human Daimyos, born from ancient Japan."
Ok what the hell? Fifty? I thought there was a total of 21. And Ermor is not new!
I think that's it.