I am trying to adopt a somewhat more flexible philosophy when it comes to Wonders--it's okay if they have a strictly local effect, as long as they also have a global effect. There will be exceptions here and there, like, the Colosseum is strong enough without adding a global effect to it, and there are modifiers in Rise and Fall that intrigue me because they would potentially allow a wider variety of regional effects (within X tiles) to be applied easily. Before, using the xml/sql files you could really only apply base yields and amenities with a regional radius but Rise and Fall opens up the possibility of attaching modifiers to cities within X tiles of a Wonder, which could be an interesting avenue to explore in the future.