This is a huge map, gives tons of room, and is very well laid out.
The only balance I can see improving is allowing the people inside the fortress to capture their own outposts. Example, say one is dwarves, they could give up an outpost to their ally, in return for a mine in their allies' area for easier traveling.
Not overly creative, but it's one of the only maps I have seen which allows two allies in a fortress together, which is exactly what I was looking for.
Inside the fortress is awesome. A huge city basically. Only flaw is it makes it a little harder to build. I had no problem finding places for mines/trees/farms... but there is more or less only one place to put barracks and other military buildings without them causing units to get clustered.
The walls of the fort are awesome, would have been great if we could build towers/catapults/posterns in them though. But I suppose it would make it unbalanced then. Still would have been very cool :) And also, would have been so much nicer to have more stairs leading to the wall. I couldn't find a good place for a building near the stairs so my units had a long walk to the wall.
Everything outside the fortress looks kinda bleak and dull. This may have been intended, but it makes it kinda boring. Some cliffs or hills would help, anything instead of a (more or less) flat expanse :)
Everything worked like it should. Had NO problems at all. Worked well on network play also.
I'm giving you such a long review because I really enjoyed this map. It's a lot of fun to play. Wish I could see more like this. Thanks!