I do agree that designing a new tech tree would be tan important step, but I do believe there are some fundamentals that should be agreed first. The Civilization V Rise of Mankind should be similar to Civilization IV's, but there should be some major differences as well, so that it isn't just Rise of Mankind 3.0. One thing that is more fundamental than the tech tree is absolutely the pacing of the game. What should be the time scales of the game? (I'm thinking eight, as with the difficulties.) What should be the time scales per era? What should be the eras of the game?
Rise of Mankind's foundation isn't gameplay over realism. The popularity of Rise of Mankind is exactly because of the people who want the Civilization series to be more realistic and historically accurate. Now, what we see is that the eras in Civilization V, or even in Rise of Mankind, are not wholly accurate in every detail. For example, the Renaissance Era generalized the time between the Medieval Era and the Industrial Era, but there were other eras during that time period as well. The Renaissance Era was generally around the time of Elizabeth I, but what about the Age of Enlightenment? That was certainly after the Renaissance Era, and, although considered in the Renaissance Era, wouldn't the Colonial Era be pretty important as well?
However, the Colonial Era wasn't necessarily important to Great Britain as it was to Spain in the 1500s, and China didn't even have a Colonial Era. Therefore, we see that the Eras system in Civilization V has a general bias to certain countries, which is obviously unintentional, but we see this perspective, if we get into the mechanics of history and apply it to the game, which is not intended to replicate actual history but to simulate a different timeline of history with the mechanics thereof we see and saw in the real world. I would thus propose that there be a wide variety of eras possible, and each country in the game would randomly get different eras, depending on the particular circumstances of the game. China did, after all, come to at least the Medieval Era, when the rest of Europe was in the Ancient or Classical Era, but then China never did go past the Medieval Era and was therefore taken over by the Europeans far into the Industrial Era. In general, however, I believe that eras should be of the first design discussion.
The reason I say these things is not to slow down progress or to be a hindrance towards the design. The reason is because, after the new ship of Rise of Mankind goes, the ability to change or repair the hull becomes much more difficult on the seas than on the harbor from which it went. Eras are the first, fundamental principle for Civilization V, because it encompasses what to do with the technology tree, pacing, and gameplay effects per era that could be added later. However, the issue of eras should be decided first, so that there is a foundation for future improvements. There is an opportunity for a new, fresh start, and we must not throw it away.
When I think about any game feature I try to add some more depth to it but still try to keep it fun - in Civ 4: RoM I think we had bit too much depth and less fun part (too much micromanaging). For this reason I'd rather not include both civic and social policy systems... one system should be enough.
