Those sound like proxies for measuring some other factors; who flourishes based on the range of ages of the surrounding buildings? Presumably that really measures some variation in the types of businesses nearby, or that there are some long term residents, or the area has some hook factor which keeps people investing over and over.

All of which they could design in or design around without having to have old buildings, say.

But it sounds like they are designing for the administration of the city, not for the end users. I wouldn't want to live there for a few revisions at least...