Mark Hope
Hero
This is a magnificent post - massive respect for the work and thought that went into this. I'm a huge Dark Sun fan and really I can't take issue with anything you've written here. Great stuff
. Like you, I was struck by the stuff in the WJ that described the Sea of Silt as being as the centre of the explored world - it's a shame that this concept was never further developed, because it's a pretty important one for a good understanding of the world imho
The population levels of the cities of the Tablelands are a source of constant debate (first listed in the Veiled Alliance book). 4e had a decent approach to this, which you have espoused as well, namely that each city-state has plenty of client villages surrounding it. This means that the population figures are urban-only. 4e says that there are about as many again living in the surrounding areas, so Tyr, with 15,000 in the city, has about another 15,000 in its surrounding villages. I don't know that I agree completely with these figures, but I do find the concept sound. Lynn Abbey, in her DS novels, added some detail to Urik's surrounding settlements, which is a good template to work from for DM who want to do the same for their own games.
And I completely agree with the idea that the various cultures of the Tablelands came there from elsewhere. If you adopt some of the later DS lore, the sorcerer-kings were once the leaders of great armies and I have always thought that they brought great trains of troops, followers, settlers, and refugees into the area as the Cleansing Wars (or whatever ancient cataclysms you prefer) devastated the surrounding world. The Tablelands are the last safely habitable part of Athas (or one of the last) under this approach and I think it fits well with the setup that we have. In my games, I rule that the people of Gulg are the actual original inhabitants of the area - there are a few bits and pieces on Gulg that suggest this - and now dwell in all that remains of their formerly lush habitat (the Crescent Forest).
I also think that the proximity of the Pristine Tower is significant. The cities ruled by the sorcerer-kings are arrayed in a loose group to the west of the Pristine Tower and I have, over the years, toyed with the idea of it being the focal point of some geomantic web that the SKs and Dragon are maintaining in order to keep Rajaat where he is, but I've never taken this idea anywhere.

The population levels of the cities of the Tablelands are a source of constant debate (first listed in the Veiled Alliance book). 4e had a decent approach to this, which you have espoused as well, namely that each city-state has plenty of client villages surrounding it. This means that the population figures are urban-only. 4e says that there are about as many again living in the surrounding areas, so Tyr, with 15,000 in the city, has about another 15,000 in its surrounding villages. I don't know that I agree completely with these figures, but I do find the concept sound. Lynn Abbey, in her DS novels, added some detail to Urik's surrounding settlements, which is a good template to work from for DM who want to do the same for their own games.
And I completely agree with the idea that the various cultures of the Tablelands came there from elsewhere. If you adopt some of the later DS lore, the sorcerer-kings were once the leaders of great armies and I have always thought that they brought great trains of troops, followers, settlers, and refugees into the area as the Cleansing Wars (or whatever ancient cataclysms you prefer) devastated the surrounding world. The Tablelands are the last safely habitable part of Athas (or one of the last) under this approach and I think it fits well with the setup that we have. In my games, I rule that the people of Gulg are the actual original inhabitants of the area - there are a few bits and pieces on Gulg that suggest this - and now dwell in all that remains of their formerly lush habitat (the Crescent Forest).
I also think that the proximity of the Pristine Tower is significant. The cities ruled by the sorcerer-kings are arrayed in a loose group to the west of the Pristine Tower and I have, over the years, toyed with the idea of it being the focal point of some geomantic web that the SKs and Dragon are maintaining in order to keep Rajaat where he is, but I've never taken this idea anywhere.