The cardinality for the references to 0..* Practitioner, 0..* Organization, and 0..* Location make this resource very expressive. It represents a broader notion of "Provider" which encompasses the notion of a single practitioner, an organization engaged in care, a care facility, or combinations of these notions, such as a practitioner working for a certain organization at a particular location. 

There are several notions that need to be expressed for a "Provider" using this broader notion of provider, such as, accepting new patients, practice age limits, language support offerings, etc.  

The current name "PractitionerRole" is misleading. It does not capture the broader essence of what this Resource can be used to represent.  The name is too narrow, pertaining only to Practitioner, when it also could be focused on a provider Organization, or a provider facility.   Recommend moving to name the resource "Provider" and fixing the associated definition.

The definition needs to be aligned also to reflect the structural possibilities. Recommended definition:   The Provider Resource describes details about a provider, which can be an individual practitioner or a group of practitioners operating as an organization. When the provider is a practitioner, there may be a relationship to an Organization. Providers render healthcare services to patients. They/He/She may render these services at certain locations,   Providers participate in healthcare insurance networks as individual practitioners, or as/through a participating organization.