Okay, total noob here.
I'm an historian and an economist, and I'd love to see Total War expand some features to the Multiplayer game. TW is up there with Europa Universalis as my favorite game of all time. Combining the battle features of TW with some of the campaign features of EU would be a dream come true.
For instance, campaign multiplayer offers the most opportunity for real fun, but the challenge is the lack of the simultaneity in playing. One player moves, the other follows. In addition, players might have jobs and other duties which gut the game of depth.
For fun, I used to play the board game Diplomacy online, and it was extremely simple, but terrific.
Each player had a deadline (e.g. 1 hour, 12 hours, 24 hours, 36 hours or even a week!) to issue orders. Those orders would then be executed once the deadline had been reached. In TW context, it could be the construction of buildings or the marching orders for an army. If all orders had been issued, the game would automatically progress.
The challenge for TW then occurs in the so-called battle phase. In a large area, two units will have a low probability of directly running into each other. However, a probability/hazard-model could, based on, for instance, the presence of light cavalry in an army, randomly assess whether one army would "discover" the other, at which point, it could then engage. Additional simple probability models could then determine the probability of reinforcements in the vicinity reaching the battlefield. The cool thing about this set-up is that it would create an incentive to divide armies up into smaller units spread over more areas/zones, which would resemble real-life a great deal more. It would provide a strong incentive also to strategically time the massing of forces for the decisive battle. During the battle/combat phase of each turn, players then make an appointment for the battle. If not possible to find a time, another probability model determines the outcome.
The potential from this line of thinking is big, but as n00b I imagine there must be certain technical difficulties. N000b thoughts!