Why the heck do you think that "lol, you use RPC" would be an insult? Because you clearly send this message with your tone.
I put RPC wherever I need an operation(s) to be called remotely. And yes, I do use dedicated RPC protocols (namely, XML-RPC, for popularity of its clients). I rarely create things that boil down to being a CRUD database interface, so I find REST very limiting.
> From that point of view, something like SOAP is a perfectly respectable protocol and you should use that instead.
Apparently you haven't worked with SOAP. No, it's not respectable. It's overcomplicated itself, it uses overcomplicated format (XML with namespaces), and its tooling is overcomplicated, too (e.g. try to control how WSDL looks like, so you can swap implementation languages; or try to create WSDL beforehand, and then implement its backend in a language of your choice).
Really, in HTTP-based remote call protocols (this includes REST!), Microsoft hit the spot twenty years ago with XML-RPC. The only two things missing are null/None/undef encoding and named procedure arguments.
