I saw this mentioned by one other poster, but I thought I'd throw in my 2c.
I'd love to see rivers in this game. Key rivers, bridges and their bombing, demolition and repair would add lots of gaming and scenario options. (My particular agenda is to make an Avalon Hill Blitkrieg scenario ... while I've seen someone else has already done their interpretation of that, I think without rivers and bridges it doesn't quite feel right to me).
Also, thanks Brit for being so active on this board!