I pretty much figured that change was not a user-friendly process.

As for the static state of these cities, would it not be most effective for the some of the greatest ancient cities? Rome, and Athens, perhaps Babylon or Alexandria...

It sure would be amazing to implement these cities. After all, these were the capitals of the greatest and most long-lived cultures of the day. It would also add TONS of character to the existing seige battles if just a few settlements were unique like this.

And they needn't be huge sprawling metropolises. Perhaps some of the more humble factions could also have there "great" city, although this would, of course, be to a lesser extent than Rome, Athens, et al.

For this reason, a static city, used infrequently for major historical points of interest, could be implemented with out affect to the rest of the system.

It would also "lighten the load" as far as effort is concerned...

If I knew how, I would help myself. But, unfortunately, I lack these skills.