Sorry for the very late response but I was a bit bussy. I typed a very lengthy reply yesterday at 3:30 am, but thanks to a bad connection I lost it. As it was so late I was to lazy to write it once more.
This time I'm going to keep rather short, as I'm not in the mood anymore to make a lengthy post. For a historical introduction I'll just link you to wikipedia this time: http://en.wikipedia.org/wiki/Qedarite
Now why you should add the qedarites instead of the sabaeans:
-Were active and lived in the area the mod's about. while the Sabaeans only had some distant trade contact, and only mingled with politics and wars a thousand miles more south in their own little remote area.
-The Qedar were international big players when it comes to politics and war. They have actually fought the assyrians. Though at certain times they did pay tribute. Later they were allies of the Persians. They have fought the egyptians on occansions as well.
-economically they were important players as well, controlling the ends of the incense routes.
-they actually fought on camelbacks, which is always a fun thing to add to a game. Sabaeans didn't (so even if you decide to pick them as a faction, you shouldn't give them camels.)
-Gameplay wise it would be a faction which has much more to offer, and isn't in a remote area minding its own business.
the reason why Saba' probably is included is because other mods have them as well, and because they are much more known. (thanks to the famous queen from the bible). They might have more information about them, but not much more in this timeframe. Most information is from the first century BC to the 3 AD and is unuseable for the mod. In other words Saba has probably been added thanks to the wrong reasons and the Qedari seem a much better option.