is there anyway the Dev's can switch the mod to 1800?
You're basically asking us to make a whole new mod there XD
Anyway, I've explained why we decided not to do anything Middle Eastern/African. But the two new factions will add new ways to fight; for example, Japan has traditional troops which excel at melee and are able to get in close and personal, so you'll need to watch those hill tops when going up against samurai because you do not want to be ambushed...
These aspects make combat a lot more interesting, not just the usual rifle stand-off. So your officers will have to prioritise the targets: who will you shoot first? The samurai charging your company from the side, or the skirmishers hiding in that bamboo over there?