The new Xbox One controller is not particularly different from the Xbox 360 controller, but it turns out that Microsoft spent some serious cash on researching new possibilities.
GamesBeat has done a series on the new controller and they revealed that MS spent $100 million researching and building prototypes which included a controller that emitted smells! Some of the slightly less weird options included built-in displays and cameras, as well as one that featured a projector.
In the end it appears that Microsoft put a lot of emphasis on what they call Golden Hands, which is basically a hard-core gamer that knows the controller better than the designers. Rather than alienating the die hard fans Microsoft decided to play it safe and just tweak the existing controller as they already believed they had the best controller out there.