Well, what I would like to see is something similiar to MTW1's different starting times. Perhaps having one at 1553 around the first battle of Kawanakajima, 1560 around the battle of Okehazama, 1582 after the Honnoji-Incident, and 1600 around the battle of Sekigahara. Other scenarios outside of Japan, like the Imjin war (which I think is a good candidate), would be the expansion. Those are my thoughts at least