I apologize for the late notice - I hope it will be still possible to discuss some of the language features and proposed changes, and to point out mistakes or wrong assumptions. Description logics developed were developed originally from as a formalization of frame based systems. It seems unlikely that every application will use a Description Logic Engine. For compatibility purposes it seems appropriate to have subProperties in Layer 1. The unique name assumption is often quite useful when dealing with large datasets.
Equivalences are usually the exception.
Viewing Property Restrictions as class expressions is a unusual viewpoint for people used to object oriented or frame based modeling. While this might be true, users of OO language of a naive understanding what restrictions are, but not how it relates to subClasses. Complex XML-Schema Datatypes currently don't have a RDF graph representation. This requires more complex processing, storage and query software. Complex Datatypes should be given a graph representation.