Have you ever looked at a non trivial schema definition in RelaxNG Compact Syntax? Its amazingly readable isn't it? (Once you've got used to the + ! ? * characters from DTDs). Now and again I bump into some RelaxNG compact syntax and think its pseudo code; but no its the real syntax specification! (e.g. in the JBI spec).
When you compare how easy it is to read & write to XSDs its not even funny. Yet it seems we're all still using XSDs all over the place. So next time you have to author an XSD by hand, consider giving RelaxNG Compact Syntax a go then use Trang to generate an XSD if you need one.
For IDE vendors; it'd be nice to have a RelaxNG Compact Syntax tab on our editors when we have to change any XSDs so we can view them as RelaxNG CS instead of all those pointy brackets and namespaces :)