Obviously because its much more fun to make new nations than to fix small, complicated AI problems.
And the reason it will be a niche game is because its too much complexity for a vast majority of our last generation to wrap their mind around. This game is a LOT of work. For me, a huge part of the depth and greatness comes from all the amazing unit descriptions. most people dont have such a creative imagination, that would take "work". TV's just feed your entertainment to you. Im not saying this is any of you, but it is a vast majority of the population.
I have no problem being a gaming elitist.