What we need are maps with a good mix of 15,000+ ft mountain ranges and flat/hilly terrain. Land shapes could be the same, but as in real life a generally random terrain would be on each land mass. That and land masses really don't need to be identical. In my opinion, the number of bases being identical is what's important .
I would agree with some of this but, remember that LAND plays apart if using Ground Vehicles, or Landing Crafts to capture a Field, not so much for Troop Transport Planes.
Even the Hills or Mountains surrounding the Field can play an important part for those Planes trying to take out the Ground Guns.
Getting this balanced out for all 3 Countries so one Country doesn't feel like they are at a disadvantage over the other 2 is the tricky part.
So if you made Fields that ( not expected to be captured with Ground Vehicles ) have similar land mass around it, say 2 mile circumference ( or more ) then the shape of the land mass wouldn't matter that much IMHO.
Pokie