A few points:
If Thri-Kreen get a bonus to AC, you need to explicitly state that they cannot wear armour. And make an item that they can wear that fills their armour slot, so they can get an enhancement bonus to their AC.
People are gonna hate the Aarakocra conversion. Especially since you give them a ceiling height - I understand why it's there, but it makes no sense in flavour terms. But that's a tough line to walk, and I don't think I'd be able to do any better. I think the encounter power is a bit boring - I imagine an aarakocra should be able to move around a lot, and the power should reflect that. Maybe a fly-by attack, as opposed to a simple 2[w] power?
I like your conversion ideas for other "non-athasian" races (such as half-orcs being mutants, or minotaurs being beast-head giants).
The conversion of Divine Clerics is a no-go, though. No matter what element I choose, I get sunk at some levels. I'd instead say something like "An elemental cleric cannot deal radiant damage; change the radiant keyword to one of these energy types instead".
You do kind of say that, but I think it could be clearer in your write-up.
Defiling as an interrupt is cool, but since PCs only get one interrupt per turn, and it's not on their turn that they cast it... I'd make it a free action, so they can still defile when they spend an action point. But I love the idea of the area becoming "Defiled", which forces wizards to move around. I can also see this playing into terrain construction - imagine squares that grant a bonus to defiling!
Don't know how I feel about the defiler's "casting track". Seems to go against the established setting, where defilers don't really sacrifice health or anything. It would also suggest the Dragon-Kings are sickly beings... which I don't really see as being true.
"Preserver of Life" definitely goes against established material. And it is a pretty damned powerful boost. A healing surge or save, once per encounter? While casting another power? Personally, I think it'd be easier to just have preservers be the "Default", and make special rules for the defiler (much like the original setting). I'd focus specific Preserver powers more on hiding their magical use (a "conceal spell" utility power), than anything that says "hey, I'm a good guy that preserves life!". My two cents, though.
Also, those rules are a bit confusing. You're essentially granting a free power to any arcane class, which makes those classes more powerful. This kind of goes against the setting, in my mind, which did a lot to encourage non-arcane character types (since they were so hated and all).
You put a lot of work into the psychic warrior. But my eyes glaze over when I read power descriptions. So I skipped for my own sanity. Not anything towards you; I skip wotc power descriptions just as quickly - they bore me to tears.
I like where you went with the paragon classes. You made some good choices.
As for backgrounds, they all seem fine. Personally, I'd follow the tradition more like the Eberron book (as opposed to the FR approach you've taken). And broaden things out a bit, so that there are multiple backgrounds from each city-state, such as a Balic Patrician, a Balic Playwright, and a Balic Freeman. And so on for each city-state, each granting different associated skills. With a "slave" background as well, that can universally be applied to any city-state. Personally, I'd make "slave" be the most powerful one, since it seems to be standard DARK SUN fare to have the PCs start off as slaves. And I'd add a few backgrounds from outside the city-states.
Literate as a feat is a great idea. I approve, and I'll steal.
Jaguar Roar is a super powerful feat (a feat that grants a daily? And one that really messes with your opponents?)
Wild Talent Feats = Awesome. In a perfect world, I'd make them be free, and taken from a random roll on a table.
Way to go beyond the material with slave prices! Well done! I was always ticked that the original books never touched on that. It would seem kind of important, considering how slavery was a huge focus of the game (but they didn't want PCs to ever have slaves).
Finally, I don't know where I stand on your weapon materials. My approach would be something totally different, but you can do it however you want. I personally think that those rules should be forgotten for 4e, and something new should be figured out, as opposed to a "conversion". But that's my two cents.
***
In all, I really like where you went with this. It's a pretty good start, and I can see this being fun enough in play. I have my own conversion notes, and they're a bit different from yours - not better, not worse, just different. I see you're working from the whole of the material, whereas I'm working only from the original set (which is how I enjoy Dark Sun).
Good work!
