What's the problem with multiple <plugin> sections for the same plugin? Right now it acts as a grouping for generic configuration.
I think it should be allowed. Take the antrun plugin for instance; you might want to run it twice using 2 different <dependencies>
defined as extensions for the plugin. They may be conflicting and need a fresh plugin realm. Or say the javadoc plugin,
once defined to generate normal html (using the standard doclet), and once using a custom doclet to generate XML, for instance.
Or an APT plugin that uses different processors, or....
If the plugins aren't stored in a Set, but in a List, there's no problem.