Comment:

Direct resource manipulation via REST does not scale well. All of the operational complexities are put onto client systems, which might be provided by multiple vendors, and are being depended on to do potentially complex operations the same way. This is especially true if we consider that FHIR is targetting lightweight, simple clients. There should be more empahsis on Operations (including more standard ones) and Messaging as a mechanism for acheiving reliable behviours.

REST is good for reading, and simple updates, but for more complex tasks we should be emphasizing operations. The situations I'm thinking of are not necessarily multistep workflows, but activities that involve updating multiple resources in a coordinated manner. A simple transaction that updates 6 resources won't detect that this was actually an attempt to accomplish a particular task, especially if the server's understanding of how to do that task differs from the clients.

Summary:

Emphasize operations for consistent behavior