You've listed changes in the other games, yet you don't see ANYTHING that's being changed in Killzone 2?
32 player multiplayer? Cover mechanic in single-player that you, your allies, and enemies will use? Hit detection, animations, and physics? Not having the same dialog lines yelled every 5 seconds (COOOOMMEEE ON!!!!!)? All that on top of the new graphics and added contrast to the colors that don't look faded and foggy?
What previews are you reading?