While creating new objects in workspace plenty configuration options are available via OIRs.
But most designers prefer to create the objects in Creo from a template stored in Windchill. At this point no attributes are available except the docType which could be send to WGM.
However OIRs can not branch today based on this information.
An holistic approach could be to introduce a filebased (standalone) and integrated (Windchill based) "Create New" dialog
Creo 4.0 will bring the Windchill "Create new CAD Document" wizard. The same wizard all other Windchill integrations have already since multiple version.