Adam Engst for TidBITS, "iOS 8 App Development Becomes a "Bring Me a Rock" Game":
Apple is in essence telling developers, “Bring me a rock.” When the developer returns with an app that seems to meet the published guidelines and Apple rejects it, the company is saying, “No, not that rock. Bring me a different rock.” Repeat the game until the developer gives up in frustration. This isn’t speculation — Launcher developer Greg Gardner wrote:
If developers don’t have explicit guidelines to go on and we can’t even use apps available on the App Store as an indicator of what is acceptable, our only choice is to potentially waste huge amounts of time working on apps that ultimately get rejected in an attempt to find something that will get accepted. I pleaded with this person to make public whatever guidelines they make available for app reviewers to decide what is acceptable and what is not regarding widgets. The Apple representative responded by saying that they prefer that the rules remain vague because that allows developers to come up with innovative ideas and also allows Apple to be flexible in case they change their minds later. When pressed on the issue of their policies leading to wasted developer time, I was told, “If you are afraid something you are working on will be rejected, then don’t work on it.”
Great piece, and a great analogy.