I would find it very helpful to be able to flip between JSP source and the corresponding container-generated Java source while debugging JSP’s, and to be able to set breakpoints in either place.
The Sysdeo Tomcat plugin manages to support generated code debug (with a few bumps) by having their project wizard arrange for the JSP work dir to be placed inside the application hierarchy. They don’t support source JSP debug, though.
–FritzM.