Known limitation. It is something we've always wanted to do and still need to do, but haven't had the time yet to do it.
In fact, its one of the first two JIRAs ever :)
There are issues with this that make it hard to implement correctly.
Mainly dealing with existing inventory - what if I already have resources in inventory and I decide to delete a plugin that managed those resources? What if I had a plugin that depended on the plugin I'm deleting? All of those dependent resources would no longer work. Lots of little things like this to think about when implementing RHQ-2.
Thanks by this JIRA ref.!
Just a comment about this issues:
"what if I already have resources in inventory and I decide to delete a plugin that managed those resources?"
IMHO I think if you want delete a plugin then you don't need more its inventory. The delete operation could ask admin user to confirm deletion and thus remove the plugin and the inventory associated with this plugin...
"What if I had a plugin that depended on the plugin I'm deleting?"
This operation could be available initially only for plugins without dependence (This could be verified at delete moment... Jopr knows the plugin's dependence graph).