I would prefer a Government/Civics system, but I think they will use a enhanced social policy system. I think they look on MMORPG's side : you choose a character, then you choose a job and finally you specialize it. They could create a similar way : you start with your civ and then have to choose a social policy (Army for example). Finally, in the military policy, you can't have all bonuses so you have to choose between 3 ways : Defense bonuses / Attack bonuses / Less expansive armies.
So you would have to choose which type of army, trade, culture, growth ... you want.
So you would have to choose which type of army, trade, culture, growth ... you want.