Where else is there an "Only for power users" feature in iPhone OS? There's no precedent for this sort of behavior in the iPhone's UI anywhere. No other built-in app has that kind of setting. The closest that I can think of is the developers debug menu in Safari. And thats not "hidden", its just tucked away because its only meant for developing and does get in the way otherwise.

A lot of the iPhone settings could be considered for "power users". There's a setting to tell the phone what to do when the home button is pressed; there's one to turn on Caps Lock, Shake to Shuffle, change the Photos' slideshow transition... they aren't unreconicilably technical, but they're subtle tweaks to functionality that power users would enjoy most.

In my informal poll of iPhone users, those I would consider non-technical also were frustrated with auto-rotation. I don't think this is something for power users only.

I'm not saying that the problem is only a power users problem. Just that the proposed solution is. A simple toggle switch somewhere in Settings.app would work just fine. Or some other solution. Just not this particular solution, a multifinger rotating gesture to rotate the device.

However, if it's an option deep in Settings, it's likely that many people who are infuriated with auto-rotation won't find it. By making the UI offer more control and responsiveness, it will help even those users who don't want to go digging into Settings.