I have been playing a game a Palermo to put the Sword of Islam DLC through its paces, and i am pleased with it so far. I would definitely say it is worth some money. I may not quite be ready to say worth $9.99, but i have yet to see all it offers.
Palermo is not a wonderful place to start as a Shia ruler. You are basically surrounded by rulers with sweet, sweet Holy War Casus Belli on you, and they aren’t shy. You of course have the same options to use against them, but unless you have managed your alliances wisely (cough Egypt cough four wives cough), you aren’t going to have the necessary muscle to fight off the extra six countries who come to their defense.
But you don’t have to sit and wait for you Vizier to fabricate claims either. The new mechanic granting Muslim nations a Casus Belli for the conquest of any foreign owned neighboring county is a thing of simplest beauty – more so if you are playing as Palermo. When surrounded by one county counts, you can take them all effortlessly, which gives Palermo the quick start it needs to survive. It is less useful once you are up against larger nations, like the Apulian d’Hautevilles, as you will need to wait for your truces to time out before taking your next county, but it does allow a slow, steady expansion that avoids the peril of declaring a holy war just upwind from the Pope. Ok, it does cost 50 piety. Yeah, that doesn’t scare me either.
Having multiple wives is also great. Often as a Christian i have struggled deciding between the trophy Stats wife and the trophy Alliance wife. A non-issue for any Muslim leader worth his salt. Your first wife is the only wife who adds to your stats, so she will need to be your trophy Stats wife. (She is also the only wife eligible to be your Spymaster.) After that you can go for the great alliances, and still have a wife left over to fish for a genius and raise an army of uberspawn. Much more useful than i had imagined.
I will be adding more info on Sword of Islam soon – both in a page for the DLC, as well as in edits to existing pages that will now need a bit of new info to explain how Islam changes things. It was without question worth buying on sale, and for those without that option, i would say you will not regret the purchase. (Not something i could say about the Ruler Designer.)