I was thinking about this last night. Its known that the rivers in that area were in constant flux, changing thier beds over the years. Why not alter the rivers (slightly) and move some of the deposits (a bit) - just a square here and there? Toss in or remove an occasinal swamp square. That way the maps stay mostly the same, but something that worked one time might not work so well in the following game.
I hadn't realized that the maps differed between eras a bit. I'm right now on the campaign, I've gone through all the sides, and now I am at the Late era, with only the Hittites completed. It's a fun challenge.
It's interesting that Bluevoss mentioned the rivers changing their course. That was a major, life-changing factor in those times, which we tried to model by changing the course of the rivers as you go from one age to another.
__________________
Alex Kutsenok
Dreamspike Studios