Work is near completion (by Surya) on a JGRoups replication implementation to complement the current RMI one. Use of JGroups for peer discovery and replication will be a configuration option. This should make it into the 1.2.1 maintenance release.
A MemoryStore built using SoftReferences. This would enable potentially much large MemoryStores with no risk of OutOfMemory errors.
Allow elements to have override TTL and TTI settings. This would have a zero processing cost and would require two four byte ints to be added to Element.
A JMS-based replication mechanism would also be useful.
James Strachan, myself and others are thinking of creating an OpenCache specification to standardise caching APIs. Naturally ehcache would implement the API.
By dropping 1.3 support, things like chained exceptions and some new collection types can be used across the board, simplifying the codebase. It would also enable creation of new features such as JMX.
Create an ehcache MBean to simplify and standardise efforts to monitor ehcache.
Please add your feature suggestions to Feature Requests.