One thing that I think all players would appreciate is eliminating the difficulty setting and break it down into 2 separate options. This way the players can select the type of bonus they would like the AI to have at the start of the campaign:
AI GAME OPTIONS
Eliminate the difficulty setting and in its place add these 2 option boxes:
[ ] AI Combat/movement bonus
Easy, Normal, Hard, Very Hard
[ ] AI Resource bonus (money, manpower, ws, rail/river)
Easy, Normal, Hard, Very Hard