Regarding detailing all (or many) of the buildings, it looks like some prefer to not have that level of detail, but have more general stuff that can be fleshed out on the fly.
I would leave at least 1/3rd of the city buildings open for GM's to put in their own stuff (that means about 2/3rd of it is, at least generically, fleshed out). Even Ptolus, as awesome as it is, didn't get that ambitious.
Like I said, it's a crazy goal, but...
Ideally the players would say "We are looking for a middle range Inn/Tavern in this area" and I can point to a few, be very generic, or throw a name of a pre-prepped one on it that fits the bill. But I'd like players to almost be able to look at the map, say "We go there. What's do they have?" and have a fairly ready to go answer for the GM if they want it. There are ways to make that possible without having a book the size of the bible.
My plan is have at
least three options for most possible results (general stores, weapon smiths, armor smiths, horse seller, gem dealer, you name it, etc, etc) and more results for other more common ones (inns, taverns, restaurants, etc). One low end/cheap, one middle class, and one fancy/expensive. But then also color code the map to designate types of businesses and have a few generic floor plans ready to go. Maybe 3-5 different warehouse layouts, 3 general store layouts, maybe a dozen or so dwelling layouts, etc.
Basically a city that is generic enough in nature to drop into just about any game, but fleshed out enough that the GM hardly has to do anything aside from give the inhabitants that matter stats.
I've got a list I've been working on of approx 250 locations so far, not including residential structures. I'm sure there's stuff I need to add (like I don't have livestock sellers or any street markets yet), but it's a work in progress. Constant progress.
