For now it is like this, not all factions will be like this.

The new Civilian unit is just one unit with two actors randomly assigned at creation, male and female. It makes no sense and it's impossible to apply different gather rates to different actors that are sharing one unit template. You need two templates for that.

For now it will be cosmetic.

The genders are purely cosmetic, there will be no difference in gameplay. Only difference is that you will no longer have 5 dudes and 50 gals while booming  

It's going to be fun. Now we have to specialize both. 

The capture system needs to be improved first, as it hasn't received many changes since A16. There should be a cooldown and an assimilation process.   The Dacians learned a little about making siege machinery from the Romans.

Yes, mountains and rivers are the best natural obstacles for walling.