OSX seems to have had this design paradigm: 'Make everything work in the most streamlined way possible for the default use case (80%). Give some limited options for a few more specific use cases (18%). Cover everything else with CLI integration / defaults system, such that the final 2% can get around with a bit of googling'
This has been highly successful, only I'm afraid that the Unix people inside Apple are loosing influence. The sandboxing in ML looks like a mess to me. Not that its a bad idea per se, but look what it did to our beautiful '~/Library/[ApplicationSupport|Preferences]'! It's tacked on and it's obvious that this has been a political decision from management rather than engineering. Makes me angry.
On a different note: I've never really used it extensively because I switched to macs in '05, but wasn't Ubuntu pretty close before they switched to Unity? I remember last time I installed it that for the first time I could have a Linux that worked out of the box, including network and graphics drivers.