After finally beat the first 2 Arab UHV with The Spiral Minaret and House of Wisdom built in my cities, I think the HoW's hammer cost arent so bad, but "double production speed with Library" would be a cool feature, if it's possible. But since the tech UHV is easily beatable without House of Wisdom, I doubt the wonder will be much of help even with triple bulbing ability, especially since you need to build lots of armies. Maybe change it to "1 free tech for every GP discoveries"? The Krak des Chevalier deserves attention here, both the current effect and the building requirements are too Spanish-sided. My suggestion is either removing the Catholic state religion from the requirements so HRE and Muslim civs could build it or make it only require Catholic so France can also make it.