There are few small, but very useful improvements in XML editing will be available in IntelliJ IDEA 10. All of them are very handy when edit XML files like schemes, JSPs, MXMLs, etc. First of these improvements is inspection detecting unused namespace declarations.
Others include namespace prefix intentions which allow you to rename, remove or introduce namespace prefixes. Want to make you schema file lighter? Not a problem:
Rename in place:
Or introduce new namespace prefix: