2 suggestions:
1. Try a normal size map. I think, for the amount of units you aim to use, it would work better. There is precious little room to maneuver the way it is now!!
2. Add some more cities! Southern France looks very empty. Marseilles, maybe? In western Germany, perhaps a city called "Ruhrgebiet?" That's the overarching name for the conglomeration of cities known as the Ruhr industrial area.
Also, is Africa on the map? The war in North Africa was a pretty interesting deal.
And what about the United States? You could put a piece of land on the far western corner of the map and place an American city or two there!