I have seen and heard the sound of unwelcome on the first preview of Adobe Experience Design CC.
Like InDesign or Illustration, in my experience this a combination of both software. The Adobe Experience Design, where you create your mock-ups for mobile and Web platforms using basic graphics and text tools, and Prototype, where you assign the flows from screen to screen. This software suppose to be a new all-in-one tool that lets you design and prototype websites and mobile apps.
Of course it has limited features such as reporting grids, automatic masking and cool features of Illustrations. This software is perfectly functional and great beginner tools. Lets wait and see on the final release on end of this year.