Blogger William Vambenepe takes the stand that Amazon proves that REST doesn’t matter for Cloud APIs. He states that he doesn’t mean it’s a poor choice, but that other reasonable alternatives (e.g. RPC) are just as good. Regarding AWS, he asks:
Has this lack of REStfulness stopped anyone from using it? Has it limited the scale of systems deployed on AWS? Does it limit the flexibility of the Cloud offering and somehow force people to consume more resources than they need? Has it made the Amazon Cloud less secure? Has it restricted the scope of platforms and languages from which the API can be invoked? Does it require more experienced engineers than competing solutions?