I am getting pretty confused. You say I am dividing the city into districts and that it is something "we" do not want. If by "we", you mean the dwarves in general, I think you are only partly right (or I am misinterpreting you). I have heard over and over again that the city should have areas solemly for dwarves, and you are saying this too, which would automatically mean you would need to divide the city into districts, as you cant have everything secluded. Take for example the trade areas and all those other areas you mention. So yes, I am dividing the city into districts, but with all due respect, you are doing the same by moving trade outside of the city.
You state that you want a "central square" in the trade area foreigners may use. In my opinion, and I think in general too, a central square is the center of a city. You are using it here as the center of the trade area, but there is no one or almost no one living here as the city is away from the trade area, making the central square a dead place. A central square is not only planned as being in the centre and being large, it should also have something that makes sure that social life is attracted to this place (this, partly, is my field of study). A central square inside the city would be such a place, a central square with only shops around it would not be such a place. My point: you are trying to create two cities, with a player base that is hardly enough to fill one.
Maybe I wasnt clear enough: I do not want foreigners to enter our city either. As such, I think we are pretty much on the same wavelength here, just a few differences. BUT if you look at my schematic, I have still incorporated the trade area in the main cities schematic. Foreigners will only have access to the trade area, and all other buildings will be out of their reach or sight. The main profit to be taken from this, is that the city and the area accesible for foreigners SHARES its central square, which is the palace. This seems fitting to me, as dwarves hold their rulers in high regard. (foreigners have no access to the palace btw). As such, foreigners get as much access in my plan as they would get in your plan, apart from the fact that we let them see one level of our palace and a small portion of our underground mountain, but still they get to see less then was the case in Karik. The main difference in my opinion is that your plan is to create two cities, while mine is to create one city, so visitors have the feeling they are "inside" the city as well, while actually they are just on the doorstep but inside the mountain.
Leland, the very thing you say you are going to do is what I am trying to prevent by reasoning, not only because I believe it would mean making the same mistake as has been done in Karik, but also because others believe so as well. I will probably not have many dwarves who will back me up on here as I mainly see high-ranking dwarves responding who are all on the same wavelength, but I have seen multiple posts on the forums stating "please do not split up the city", "please keep it simple", "please do not make a long hall with buildings along it", "please do not spread out the city again".
Let me finish my maybe fierce wall of text with the fact that I very much enjoy this intelligent discussion and that sharing different point of views will eventually always lead to better decisions then those made by people who all share the same thoughts.