I think it's just because 10.6 wasn't a very UI-oriented release. There were lots of changes under the hood, but since the design awards are usually awarded to

I think it's just because 10.6 wasn't a very UI-oriented release. There were lots of changes under the hood, but since the design awards are usually awarded to software implementing cool new OS features. Software that implement Grand Central Dispatch or OpenCL in an awesome way don't correlate with the design of the app, so it's hard to give them out meaningfully. I don't see the problem in giving out awards for the platform they're focusing on any particular year -- I just hope they don't pull all the best engineers from the Mac OS to the iPhone and let it slide for too long.