I also noticed that envers is adding a revision each time I save an entity, even if I don't change any data. If it can help, I'm using spring and jsf.
My hibernate properties:
<prop key="hibernate.hbm2ddl.auto">update</prop>
<prop key="org.hibernate.envers.track_entities_changed_in_revision">true</prop>
<prop key="org.hibernate.envers.store_data_at_delete">true</prop>