I'm working on the tech tree today (ensuring all civilopedia entries are completed as I go along). Before I started this morning, Anno Domini only had 18 techs - I was playtesting for the artwork and learning how to actually mod Civ IV. Up to now, I've added an additional 40-50 techs for one very long ancient age. There'll be a classical and medieval age (perhaps renamed to the Dark Ages or Feudal Age - or I could even call the ages Anno Incepti, Anno Imperii and Anno Domini like in the Civ 3 version), which will comprise approximately 25-30 techs each. Luckily, I did a decent civilopedia for the Civ 3 version of the game, though it wasn't complete. However, I've been able to transfer a large quantity of information from there, which has saved a lot of time.
I'm going to be introducing the various civic options at some point soon. I think I'll keep the following as they are:
Government: Despotism, Hereditary Rule
Legal: Barbarism, Vassalage, Bureaucracy
Labour: Tribalism, Slavery, Serfdom, Caste System, Emancipation
Economy: Decentralisation, Mercantilism, Free Market
Religion: Paganism, Organised Religion, Theocracy, Pacifism.
Any thoughts? Any ideas on what I could add?