This bug/feature prevents us from properly maintaining JIRA instances.
This is needed in order to be able to query existing fields and to find out which one of them is broken.
On any big JIRA deployment administrators need to be able to detect and fix broken JQL filters, any change made to the custom fields can break them and you need to be able to detect the affected ones.
By providing this functionality you would allow people to implement this maintenance scripts.
Currently admins are able to browse the filters in the UI, but that kind of maintenance does not allow them to test and doesn't scale for more than very-small jira instances.