My favorite Campaign is the Japanese Rising Sun.
I feel like a player-made Campaign or a DLC (Pacific Domination) to follow-up the original game would be fascinating and enjoyable.
Suggested scenarios:
- MIdway Redux
- Aleutian Expanse
- Eastern Redoubt (Conquest of the Hawaiian Islands)
As I lack ...

I still have no idea what you do with those 90+ units on the right side of the map, notwithstanding the explanation above.