While this is a cool idea, if I were going to try and make BM more like the Civ games (which, by the way, I am addicted to), I would do it with technologies, not world wonders. Nowhere near as deep a tech tree as in those games, but things like spiral fletching for arrows, more advanced tactics...I have a list somewhere, but no brain right now.
Oooo now that IS a slick idea...like if the realm researches better arrows then all ranged RC's kick up a notch right? That should def be in a different thread. Would World Wonders be an exciting asset? I certainly think so!