Gartner's "Hype Cycle for Governance, Risk and Compliance Technologies, 2014"* puts "Externalized Authorization Management" (EAM) in the "Trough of Disillusionment", stating that "Gartner clients have reported that maintaining a fine-grained access policy across a large number of custom or complex applications can be a daunting and expensive proposition". In line with this, we have discussed many times in most of our own publications for over a decade) is that authoring and maintaining a large number of fine-grained EAM access policies across many applications is expensive, difficult, time-consuming, error-prone, and non-traceable. This is especially true for attribute-based access control (ABAC), which supports extremely rich and flexible access rules.
However, it is important to note that Gartner's "Hype Cycle for Governance, Risk and Compliance, 2014" category is "Externalized Authorization Management", and not model-driven security (MDS) used with EAM. For over a decade, we have shown that MDS is an ideal candidate to resolve EAM's manageability/complexity challenges. Over the years, we have carried out many MDS deployments (over EAM & ABAC) over the years, implementing highly complex policies. MDS works best if there is a human understanding of the policy that is general, intuitive, simple, and human-intuitive. MDS (like EAM & ABAC) requires access to a number of attribute sources (and often also attribute mappings) to turn this general human understanding of the policy into the detailed technical rules that can be technically enforced (e.g. by EAM, ABAC). This can be a challenge, however the resulting level of automation, manageability, usability, support for system agility, and traceable compliance by far outweigh the costs.
An example we have recently designed and implemented for a customer is something we tentatively call "relationship-based access control" (RelBAC, we also call this a highly enhanced, multidimensional "proximity-based access control" model) - humans are usually great at expressing general access policies based on the relationship of themselves (or something they are associated with) with something they are trying to access (or something the accessed resource is associated with). Due to restrictions we cannot post too many details here, but please contact us if you would like to hear more about this.
* Gartner, Hype Cycle for Governance, Risk and Compliance Technologies, 17 July 2014, John A Wheeler