I can understand why they would cut out dynasties: there are more important aspects of the game to work on and not enough time to flesh out the preexisting, though underdeveloped, dynasty system. I would've like to see diplomacy based in part on arranged marriages rather than solely on trade. I really hope the dynasty concept is not dead and will return in the 3rd game.
In all honesty, I feel like the new vision is less of a 4x experience and more of a rpgish war game. While this might be a fun experience, especially with the new uber monsters, it won't hold my attention for long unless they go out of their way to greatly improve tactical combat and make the various factions feel unique.
In case you missed it, Derek gave one example of how factions will be made unique: One of the Empire factions are stronger then the regular Joe, so they'll be able to carry a heavier load of equipment --> the best soldiers in the game. To me that seemed a step in the right direction.
I think I understand what you meant about an rpgish feel, but if you remove the sovereign and champions, it is pretty much the same game as Gal Civ 2: without the espionage, but with the tactical battles.