In looking over this I don't see any real holes, but I do have a couple of questions. How does the CachedConnectionManager play into the JCA container now? Is it still a hard dependency? If its still there, it would be really great to be able to remove it completely from the configuration.
I like the fact that you will be able to turn on and off the statistics, as we will be able to directly measure the difference, and it probably helps with the benchmarking activities. The one statistic that seems to be missing is the max connection count in use, which is probably also the worst from a performance perspective. Was that intentional? It seems like you could just use the created count for that, if it was greater than the min and less than the max anyway.