If you are using EJB or JPA spec apis you end up with a module dep on the new version automatically being added.
See: https://docs.jboss.org/author/display/AS7/Implicit+module+dependencies+for+deployments
We plan to add a feature in a future release (7.1 at the latest) that allows you to install custom JPA providers. Optionally, if you are using hibernate directly, and the JPA inclusion isn't really used, you can exclude the auto hibernate dep (see exlusions):
https://docs.jboss.org/author/display/AS7/Class+Loading+in+AS7
Note that the reason that we have to have some kind of provider/implementation is that JPA has all kinds of requirements about how the container should process the deployment. E.g. @PersistenceContext has to properly injected at certain times in the container lifecycle and properly interact with the TM. So a standalone library, wihtout any kind of app server integration is going to not be 100% operational