Cameron, thanks a lot for your valuable feedback, in fact I believe that thanks to this kind of opinion and concrete problems jBPM will become more mature soon as well. I think that significant step has been taken with 5.3 to provide smooth integration with JBoss AS7 and hibernate 4 and prior to that hibernate 4 (JPA2) was not supported at all. I am not saying that we are all good but it is step in right direction and will are going to continue to improve in this area as well.
I would like to encourage you to create jira for things that you would like to see in the upcoming release as that help us to prioritize work and we appreciate community feedback and involvement.
Cheers
Maciej