Now that you mentioned it...
I find the model qutie sensible, but it seems to describe only half of what goes on in AI, namely the behaviour and how it is structured. However, I think that there's a whole another side to the way the computer operates: the way it observes the world. What does the AI know about the game world? What's the underlying model or worldview it operates under?
Now, of course it is taken for granted that the AI knows what the game engine tells it... position of units, terrain, so and so much money in the treasury et cetera. But, in addition to all this AI should be able to grasp more abstract concepts like fronts, feints, bluffs, defensive or offensive units, strategically important cities/places, and so on. Perhaps this could be implemented in kind of another tree-like hierarchy parallel to the one described earlier, and the "plans" might use this information when determining actions?
(...but what do I know )