> And the iOS approach, though it has inconsistencies, actually makes a lot of sense, with the 'content is king' and 'depth through translucency' approaches.

I think that's the key difference. The 'content is king' approach is great for consuming visual content but less good for applications that are not about content consumption but about interaction. If I'm reading a website, I want the UI chrome to get out of the way and not distract me visually - on the other hand if I'm trying to reschedule something in my calendar I want the options and interaction points available to me to be obvious so that I can make the change quickly and accurately.