I love this type of game. There is endless awesomeness that could be made. Large cities, provinces within countries, counties within states, language areas, ancient empires, historical political maps, seas, topological feature names...
Trap level tips: Make your heroes follow entering enemies. Against crowds, space them out a bit along the track so they shoot different enemies. When enemies enter at different points, cover each point with a different hero. Use your spells! Use your hotkeys! The level is not easy, but it's doable.
This is fun and addictive! My only real complaint (though it's a major one) is that the visual indication that a spell is ready to cast is nowhere near noticeable enough. I'm constantly trying to cast spells that, it turns out, haven't quite finished their recharge timers.
We've got players who intentionally use the tank movement round to make sure that all tanks are juxtaposed on top of one another in a huge dogpile, simply because it increases weapon experience. Something should be done about this.
Fantastic game! Things the game needs: (1) the ability to break off an attack; (2) more visible way of showing which unit is selected; (3) a way to turn of the blasted auto-center when selecting a unit via hotkey; (4) a way to turn off the facebook feed pop-ups with every new achievement.