Scrolling through the Dark Sky screenshots, I can recognize many of the same things now incorporated with Apple’s. And Apple does offer location specific notifications of rain which I find to be pretty accurate, about as accurate as Dark Sky.
There’s largely a perception problem with Apple. People loved Dark Sky as an independent small app that worked well, before Apple took it and destroyed it. Now, even if Apple incorporated all of the same data and features, it still wouldn’t give that same spark of joy people had.