Let's talk about the idea of a player's focus, and how I apply it to strategy games and game design.
A player has a limited amount of concentration or
focus when they play a game. If the game takes more focus to play than the player has, they percieve your game as being
monolithic or
impenetrable. Paradox grand strategy games are known in the community for this: having so many moving parts that beginners have difficulty keeping track of everything. When I initially began playing Paradox grand strategy games (Europa Universalis, Victoria), I had trouble keeping track of everything. With practice I was able to manage more things, but in the end the games require more focus of me than I have. So I end up leaving certain areas of the game completely alone.
Players also define a game based on where they spend most of their focus. If I spend the majority of my time in a game maneuvering units and managing conquests, I consider the game a wargame, no matter its stated genre. Civilization 5, for instance, is much more a wargame than an empire-building game to me. When I play, practically all of my time is spent managing units and warfare. Conversely, in Civilization 4 I spend more time planning my tech priorities, managing city production, and planning worker actions. Wars are short and to the point, and even during long wars the main focus is on training new units and bringing them to the front. Civilization 4 then, to me, is an Empire building game.
The places in your game where a player spends his focus then, will shape what the game is about in that player's mind. At a certain point, the Magic system in Fall From Heaven grabs more mindshare from the player and focuses it on units. This isn't necessarily bad, but it's important to recognize what happens as we drive the player's focus towards units and away from empire management.