The choice of monsters: Quicklings, spriggans, and a fang golem just felt... out of place. I know there's a fey portal at the bottom, but those monsters just didn't seem to .. fit. The satyr, though, seems to fit.
The quicklings, spriggans, and fang golem are Emrett's minions and are not native to the Oasis (the same goes for Taalah and the satyr).
That first encounter, with three soldiers? Ouch. There's also very little in the way of giving PCs clues to where to go - unless they Skill Challenge it out of a captive. Which side of the Dune is the leeway, and which is the Wind side? Also, 'it's difficult terrain, but if you succeed in a skill check, moving is normal'; it becomes normal terrain if you succeed in the check, or remains difficult terrain?
Yeah, I'm don't normally favor loading an encounter with a bunch of soldiers, but since this is likely to be the only encounter that the PCs face prior to their arrival at the Oasis (unless the DM adds encounters of their own), I thought that pushing the PCs to their limits would be OK. Its definitely a tough encounter, as I was told that during the WotC playtest, it almost ended in a TPK (curiously enough, the main culprit was apparently the war camel).
Originally, there was a skill challenge that covered the journey to the Oasis, but in terms of word count it was very lengthy and I was told that the DM who ran the playtest felt it fell kind of flat, so it got cut for space. That said, we should have probably made it clearer that even after encounter D1 concludes, the eladrin tracks are still easy to follow. I should have also made the leeward/windward issues clearer on my map turnover since its really only depicted by the relative closesness of the elevation lines; the windward side is the east slope. As for the sand on the windward slope, you need to make the skill check to move, but its still difficult terrain.
You give a PC an automatic arcana check for the corralaxes, right? I doubt a PC would instinctively check the threat of birds sitting in the tree.
I would personally handle it with a Passive Arcana check, but since they're explicitly called out in the description, I would think that some players would call for the check on their own.
The lovers nest is indeed a great encounter. The only problem I find with it is that if the PCs don't attack Taalah, then a lot of things don't happen (Saqr doesn't get to use some of his powers, the Quickling and Taalah stay out of the fight). Because I doubt most PCs would attack a naked and defenseless woman, the above outcome is likely. At which point the encounter (aside from the situation) isn't that interesting; Saqr by himself, without his cool Taalah protecting powers, is rather boring.
Even though she's a naked and apparently defenseless woman, I always figured that at some point either she'd get caught in an AoE, or someone would see through her
deceptive veil, or she would attack at some point, or would try to subdue her (or the party just doesn't care and subscribes to the the kill 'em all theory) etc., but I also worried about some of the issues you identified (not the quickling, as I figured that the PCs just having to act threatening towards Taalah would give the DM a lot of leeway). When I built Saqr, I did think about giving him some additional powers, but I didn't want to go overboard since he was a Brute; hopefully,
tower of sand,
fey step, and his threatening reach are enough to compensate (as well as the introduction of the quickling to the battle) if the PCs don't actually attack Taalah.
Really like Hazar's stats. However, her tactics are BRUTAL. It will be a pain in the butt given her flight to hurt her for any non-ranged PCs. Also fighting her in the nest is very bad, given that the party is going to get a sentinel patrol up in their face.
Definitely, fighting Hazar in her lair is probably suicidal. Hopefully that will encourage PCs to try to the non-violent option
06: What are the red lines on the map for?
Are you referring to the elevantion lines?
I agree with Merric's observation on his blog that this is difficuilt and curious, as it makes a great use for a campaign. Wiggling it in earlier, with Voor. Emrett makes a great villain purely by her personality and actions in combat, so it's sad that the PCs only encounter her once. And as Merric points out, given that it's a desertadventure with an arabic feel, you gott ado some work to make it "work" in your setting.
However, this adventure is great. Especially teh arabian feel of it. A lot of work was put in and it's got several gems.
Thanks to both you and Merric for your comments. As for Emrett, even though she technically only appears once, I wanted to foreshadow her and her personality in earlier encounters (through Farooq, any captured eladrin, her diary, Hazar, Voor etc.); in addition, there will be a Side Trek coming out in the near future that supplements this adventure and can provide even more foreshadowing. I hope everyone enjoys that one too.
Like finding a giant in a cavern full of undead. Even if there's a reason for it, it does cause a "Wait what?" doubletake. 
