The problem with RPC style calls is you can't take advantage of "natural" server features like caching and such. You need to re-implement all this on top of both the client and the server.

I agree with your point about REST though, it's not even a standard. If it was there would be no debate about what REST is and what it isn't. It's a vague set of idea and its author himself kind of said his paper was targeted at "specialists" and not classical "developers".

People keep on telling me "read the spec", well there is no normative spec.