As much as anyone who uses AWS and its various client libraries can attest to the areas this manifesto didn't solve, I think it's still very much the right way to go, and I think the success of AWS was at least significantly attributable to it. I've been part of several projects whose goal was to build Good interfaces on top of services after the fact, and I'm absolutely convinced that the shittiest interface in the world built in from the start trumps whatever you think you're going to be able to do later.