One needn't look further than Windows Phone 7, with Metro, as an example of how to do an original smartphone and tablet UI. Google could have ripped the guts out of the underlying interface assumptions that Apple made and did something completely different, but they didn't.

I'd personally prefer a competitive landscape where players do what Harris's team did at Microsoft or what Palm did with WebOS, which is to make it their own. Tiles instead of icons. Cards for switching and closing apps instead of iOS's in and out. Big players who copy are bad for innovation, not good for it.