Azure needs a tagging metadata store similar to SharePoint...for policy construction.
Azure Governance / Policy for tags needs a major addition in a core metadata store for tags that can be provisioned at a Management Group level and then assigned to assigned Subscriptions. Then that store/database can be used to define an array of policy parameters when creating resources that require a set of tags.
Alex Uy commented
In line with this request, I have a customer looking to create a policy for specific RGs on a case by case basis. If the RG is not enforcing the governance tagging model it will be locked within 24hrs.