I really wish someone would re-write all of AWS documentation and make everything simpler to understand. I'd like to use AWS but the documentation as-is would take hours to read.
Within each SDK, I find their API relatively easy to use. Each method is pretty well documented (certainly not perfectly).
For the most part they are created via code generation (to my knowledge), which while not necessarily making for the best user-friendly API (Although it's not bad), does make it fairly consistent in terms of groking how to accomplish automating a task.
I thought the documentation is pretty well written and comprehensive. Probably the reason why it appears complicated is just because of the nature (and amount) of their services.