It seems to me that each zone basically has one city that's intended to be "the main city" in that zone, meaning the one where the crafting writ boards and the turn-in crates are.

This "main city" is not necessarily the largest one in the zone, and does not necessarily have any player housing available, but by virtue of its crafting writ boards and turn-in crates it seems to be where players are expected to "live," or hang out from day to day, while they're residing in that zone and aren't running around doing quests or other activities.

There are all of the crafting stations needed for doing writs, which means there's a tavern or inn where players can craft food and drink and buy basic recipes from a chef and a brewer, a Mages Guild and various related "magely" support buildings with vendors and crafting stations for alchemy, enchanting, and jewelry, as well as a Fighters Guild and various "warrior" support buildings and vendors who sell armor and weapons (even if no one but rank noobs ever buys the armor and weapons), a bank, an outlaws refuge, an outfit station, at least one guild trader, etc.

There might be one or more additional cities in that zone which are almost suitable for day-to-day living, having a few or even several of the facilities needed by a "main hub city," but they will lack some of the key facilities that characterize a main hub-- in particular, no crafting writ boards, no turn-in crates, and no outlaws refuge. But otherwise they are "almost" main hub cities, and in fact might even be larger and have more guild traders than the zone's "real" main hub city.

And then there are cities or towns or farms that typically don't have any facilities to speak of, which are usually besieged by an enemy alliance or overrun by some kind of threat-- plague, ghosts, spiders, giants, daedra, etc. They seem to exist mainly as places where you need to do portions of their zone's questline, or just miscellaneous quests. In some cases they have a few facilities that become available once you've saved the day there.

Hallin's Stand is the latter type of city.

Is this a good design? I don't know. It's an interesting design, but it doesn't always seem to make a lot of sense.

For example, Vulkhel Guard is clearly meant to be the main day-to-day hub city in Auridon, since it has the zone's only outlaws refuge, as well as the crafting writ boards and turn-in crates, and is even where the Impresario shows up whenever an Event is in swing-- yet it has only one guild trader, whereas Skywatch has several guild traders as well as slightly larger player housing.

Abd then there's Davon's Watch, which doesn't even have any player housing, whereas Ebonheart has "the free" player housing in the EP alliance, as well as more guild traders than Davon's Watch.

I like them as well. They're the only cities where roleplayers are almost free from griefing if they want to do open world RP.

Yeah it seems the closest city to the starting area of the zone's main quest is going to be the main city except in certain scenarios. (i.e. Alinor, Wayrest, Mournhold, and Elden Root.)

Even if another city or town is bigger it's classified as a minor settlement and thus the devs didn't put anything there. See the same thing with cities in the minor DLC zones like with Markarth lacking a writ board despite having the best crafting area and an outlaw's refuge.

writ locations and undaunted in every city is what i always say.
oh and BG stuff too i guess.
only master writs be relegated to capitals only.

Not everything needs to have a functionality. Having less circulated places, out of the way, is only realistic.

That said, it would be cool if we could kill NPCs and take over their houses like in the other games.

There's something about the Gold Coast, and Kvatch that it is just the main city for all my characters.

I like it's look,the Arena is a fun distraction, and I own Erstwhile Sanctuary.