personally, i think there should be two different types of campaign mode: one which has Total War-style gameplay, and another more like traditional RTS campaigns, along the lines of what was presented in AOK, with a linear storyline and setup to tell the story of a historical character or setting (such as, for instance, an Alexander Campaign focusing on Alexander the Great's rise to power, the Siege of Tyre, the conquest of Persia, and all the way up to the attempts at conquering India and, perhaps at the very end, giving the player a non-linear option to choose one of the Diadochi to play as after the scenario starts and getting different goals as a result (Empire Earth: The Art of Conquest had this in the last level of their Roman Campaign, where you could choose to side with either Cleopatra or Ptolemy and would therefore have to conquer either Alexandria or several fortresses in the desert; in-game, this was done by selecting a Diplomat unit controlled by the respective parties, which prompts a couple of tigers belonging to Caesar to devour him and turn that AI player against you ) arguably, a linear campaign would be easier to design and manage, and has been the mainstay single-player mode of pretty much every well-known RTS in the past