I don't think that's Apple losing its way, more just the operating system having matured. They're still adding some cool features (Continuity being the latest major new thing) but for the most part, it doesn't change much.

The same is happening on iOS really. It's becoming more and more boring - in a good way. It's reached a point where it's pretty much complete and now they're just tweaking bits, adding a few new features as things become possible, etc.

Windows 8, on the other hand, was really exciting - but not in a good way.