I'm also an Amazon Prime member, but their streaming catalog is abysmal -- I mean, it borders on embarrassing. I check it every now and again when Amazon uses the home page to tell me all of the 'great' new content they've added, but going back to the Netflix comparison, by that benchmark, it doesn't even come close.
I've never run into an issue with them hiding content. I'm not sure to what you're referring. They didn't plaster Iron Man 2 all over the landing page when it became available?
You can more or less watch the views flood in on instantwatcher.com anytime a 'modern' movie is released on streaming. It shoots to the top right away, which makes me think that, for most people, finding the 'good' content is not an issue.