I've only just skimmed it, but a few things jumped out at me (apart from the gold ink, which I find I really don't actually like very much):
Chapter 1 The Land of Fate starts like this:
Does anyone know of anyone that has used Arabian Adventures in any campaign world other than Toril?Arabian Adventures Chapter 1 The Land of Fate opening paragraph wrote:While the Arabian Adventures rules can enhance any campaign, their official setting - the location in which Al-Qadim accessories and adventures takes place - is Zakhara.
In Chapter 2 Characters, I really like the "Station in life" rules (pages 20-26).
Chapter 3 Character Kits has some very interesting kits and I wonder if anyone has ever mapped them to the regions (for example a list of settlements that Askars could hail from). The Ajami are pretty interesting. I wonder how alien you could make a wizard. Maybe this would be a good excuse for a spacefarer character in Al-Qadim!
The religion of Al-Qadim seems fairly interesting. I'm not sure I get it all yet, but the Hakima kit is a very interesting idea. (I love the idea of a wise woman powering a spelljamming helm! )
Chapter 4 Proficiencies looks pretty much as I would expect it, although I'm not sure that things like "Horse Specialisation" should be specific to Al-Qadim. I think that The Horde should have that one too.
Likewise, Chapter 5 Perils of Adventuring, has some rules to penalise bulky armour worn in the desert. I think those rules could be applied to Maztica (and other hot settings and sub-settings). The Dehydration rules seem pretty interesting.
Looking at Chapter 6 At the Bazaar, I'm wondering if the barijah, either of the canoe types, a launch, sambuk or zaruq would be useful as a groundling ship in Realmspace. Does anyone know if deck plans have been made for any of these?
Chapter 7 Sha'ir Abilities looks like one of the most evocative parts of Al-Qadim. Genie prisons look like they could turn up in other campaign settings. I like the rules for meeting genies. They could be useful for roleplaying genie culture in other settings.
Chapter 8 Wizard Spells is also going to be another iconic chapter. The Ship of Fools spell looks like it might be an interesting way for a Zakharan spellcaster to get an advantage over a non-Zakharan ship.