Well, I like the idea of what you propose, my question is, what was the status of the project before deciding to rework? Is it Like TTM where it revamps the system, or more like EDB's Scenario System?
As for eras, the best would be to do like civilization or age of empires, and do the major ones, Stone, Bronze, Iron, Dark, Industrial, Nuclear, modern, Information/Computer, Cybernetic/Bionic Ages and maybe a soft endgame being called Interstellar, (where you incorporate the already implemented offworld transport system). The basis of each Age sounds pretty self explanitory, and Google always provides decent examples if you are confused upon what a specific age would be.
It would help a bit more to know what your goal(s) for ages are, and what in specific you are looking for insight upon from the General Public.
Well, I am a wonderful Idea guy if you need someone to bounce ideas or thoughts off of. And when the time comes, I would be totally willing to be a Mod Breaker Play Tester for you. both with other mods and straight Vanilla with your mod.
I will definately be checking in on this for status updates on progress, because you my friend, have piqued my interest.