full status dump operations from JMX beans (two methods, one std err onr to logger at INFO level?) 

Statement cache statistics exposed via JMX.
Interface to Statement-caching statistics

make asynchronous checkins optional, let the default depend on the value of testConnectionOnCheckin.

A shortcut in acquire tasks that bails before attempting an acquire if the acquisition
is no longer necessary.

Make visible rootCause exceptions when Connection test fails. (Looks implemented, but I don't see them. Debug.)

Less confusing hibernate ConnectionProvider.

JUnit testing regime.

some validation stuff in C3P0PooledConnectionPoolManager...











