The next big feature will be a decent IDE integration to Eclipse with visual editing capabilities. Couple of tickets related to these are:
http://dev.itmill.com/ticket/98
http://dev.itmill.com/ticket/1266
Design draft for Eclipse plugin can be found here:
http://dev.itmill.com/raw-attachment/ticket/98/ToolkitEclipsePlugin%20-%20draft%201.pdf
Please comment on design. What is missing? What is wrong? What could be left out? Any ideas on implementation strategy?