I agree XACML has lot of complexities. But if you look at the recent developments, you can now have both XACML request and response JSON based - and the communication between the PEP and PDP in a RESTful manner. Also - there is a standard coming up to have a JSON representation of XACML policies. BTW, this blog only presents an architectural model - it can be any policy language. Recently I found Netflix uses the same model for policy distribution but instead of XACML, uses PADME. For me more than the language, the issue XACML having is maintainability, auditability and governance. There are tools around to support that. Even PADME does not solve these problems.