There should be a map that has no bonuses of any type, as that doesn’t really make much historical sense.
Instead, every territory would automatically generate 1 or more troops per turn (desert might generate 1, the Nile might generate 2 or more, sea spots might generate none, etc). You could reinforce as much as you like, of course.
Every territory could have a peak number of troops that could end a turn in it at a time, same as before. Instead of warring “hordes of doom” that wear each other down, you could have actual war, with planned-out campaigns and decisive victories, instead of massive hordes, suicides, and constant attempts to break enemy bonuses.
Actual map concepts: North Sea and surrounding land, connect-the-dots (making pictures=bonus), and Mars with Oceans.
I suggest Mars With Oceans because it would give geographically interesting maps (which is hard) without looking artificial.