I think some small variations on this idea could make it pretty fun. There's some good concepts hiding in there:
- The way that you need to fortify your border to protect yourself from being taken over, but this is less efficient economically than fortifying your interior.
- Since defense is so much stronger than offense, when you attack a territory you need to have enough resources to take it completely--otherwise, your opponent can quickly fortify it back up again after.
Maybe this would be better if it were turn based, and if the computer played a little bit better. As it is, the computer is too dumb so the optimal strategy against it is very boring.