I'd like to see a language available at the item level. You can derive the language from the http headers but if you're dealing with linkblogs it would be nice at the item level to help with filtering.

I think that images and urls would do well as order lists rather than as individual values. at the top level you have 3 urls and an array for hubs. with type and url you could have an array for hubs and the urls. same could be done for images at the top level and both again at the item level.