Thanks for idea but I don't think C2 will implement any cache editor any time soon due to the time required.

It's quite easy to export the cache to XML and then use a XSLT stylesheet with Saxon (http://www.saxonica.com/download/java.xml) to manipulate the cache.

Using Saxon also gives you access to XSLT/XPath v2.0 and v3.0.

If I would build it in C2 you could only use the XML library that comes with Java and it only supports XSLT/XPath 1.0

Also it's much easier just to add a temporary policy on the subscriber event channel and veto the events you don't want