@Snow regarding armies
That does sound interesting... something like your city cap being your army cap, with Industry advancement increasing the army cap. It does make a bit more sense than it increasing the amount of cities you have towards DV's army generation suggestion. Whether you'd want to consider this mixed with DV's Risk suggestion for army generation is debatable, but I could see them playing nicely together.
@Snow regarding Advance City
Toast has it correct. Having Advance City count as a normal city wide advancement (which can be stolen by taking the city) is actually one of the suggestions on the board.
@Draykin regarding Significant Figures
...and I can see what you want, but there are three problems.
One, Avatars are really versatile; we just don't use their versatility that often. In the first game, I had an avatar that was a dynasty of my evil empire that never got to be evil. In the second game Toast had an avatar that was essentially a mortal avatar before he ascended to demonhood as part of a catastrophe, and Donnie created several mortal avatars during the last few turns to represent prophets and generals for his pompoms. Not much like that has happened in the current game, but there was still creativity in the form of Snow's item avatars being passed from hero/merchant to hero/merchant.
Two, turn timespan. The first phase has turns as centuries, the second phase has turns as decades, and only the third phase has turns measured in a span of years. We certainly can't have Significant Figures stick around, but if you just want them to be historical notes... then they may as well just be flavor text to Advancements and other actions. And if you really want them to be different than advancements then...
Three, advancements are still on the drawing board. Yes, I really have my support by the one I suggested, but we still don't have consensus ... I really don't think we'll ever get clear consensus though. We're a group of people talking about the game we want to play ourselves, with people popping in and out of the discussion and sometimes just not responding to some ideas at all. Most likely the third game will eventually end and whoever decides they can handle story managing the fourth game will start a new thread and announce what rules they are going to be using. Which is probably a good thing since we're not going to be sure how good any of these rules are until they are tested and it might be over ambitious to test ALL of them at once... while at the same time these games take so long it would be insane to just add one change at a time.