Yea, the reality isn't near as good as it looked in the advertisments.

Haven't looked through the building file yet, but the only thing I've found so far is that the everyone who can build christian shrines can make priests/monks. Some of them can also build monastaries (sp?) which give 5% happiness per level. And the Franks can build Paladins (just another heavy cav unit. Decent, but nothing special.)