What does the complexity matter? Either way you're running some service description file through some build tooling to generate some human unfriendly code. Who cares how big or complex the code in the middle is?
Because in most cases that I have experienced, no, you are not running the sdl through a generator to create a client. You are instead instantiating a http client, setting the right headers, urls, package bodies etc, all by hand. Something which is done in lieu of using a code generator because its trivial with an HTTP web service.
Furthermore, with an http api and depending on your security model, you can test/inspect a good portion of your APIs directly with a browser - a zero-cost client for all http apis that you get for free.
