Not that fast to get it from a video, but from its wiki: "As the player advances through the ages, and erects more structures within the city limits, the city will expand, increasing its defensive power, gather rate, and extending the national borders, as well as its own radius". Indeed I had forgotten, this is a really nice mechanic, I prefer it to going village->town->city for all CCs at the same time. What ruined RoN for me was the automatic transport ships after building a dock.   I think I've read this being discussed, and indeed it would be worth having the option, no need to impose one or the other.   I don't tend to agree with this, because there are many ways in which something can work, and no one resonable proposes "change this without any testing, because it works in my mental emulation".

In this game, you can always rebuild even if you’re down to a single unit. This happens quite often in team matches. A player might lose their entire base but still have a few units left; even without enough resources, allies can share the bare minimum needed to bring them back into the game. Instead of breaking something that already works, it might be worth considering adding an extra victory option, something like “last CC standing,” so no one gets frustrated (especially when playing against the AI) searching the entire map for that last unit. As for the other buildings, you just need to wait a few seconds for them to lose control.

Few players do it. I don't bother with anything more than a couple of fields and some towers. Maybe a Temple and a Fortress if it's a forward CC. You can remind yourself by watching a couple of Rise of Nations gameplay videos on Youtube.

Carthaginians bring wealth and prosperity to Kush. Played against a Hard Petra on Marmara map.   Cart_VS_Kush_H.zip

Nice work @Alexandermb I believe that the earth is a bit too bright/saturated.