Rather than defining the web service to retrieve different layers (wms request=getMap), I'd suggest to provide / expect metadata describing the request=getCapabilities service; that service does not only provide the list of layers available, but also extended metadata on these layers (e.g. layer-specific projection lists, abstracts etc.)
Further, the layer list would be dynamic, not requiring the change of dcat metadata if layers are added/removed.
(improvement, actually not of the dcat definition but of the way how it is used, and of the depending applications)
Rather than defining the web service to retrieve different layers (wms request=getMap), I'd suggest to provide / expect metadata describing the request=getCapabilities service; that service does not only provide the list of layers available, but also extended metadata on these layers (e.g. layer-specific projection lists, abstracts etc.) Further, the layer list would be dynamic, not requiring the change of dcat metadata if layers are added/removed. (improvement, actually not of the dcat definition but of the way how it is used, and of the depending applications)