There is. It's made by Apple, has the app store, and the Apple ecosystem. That's enough to warrant the premium price tag.
I don't agree. While I agree that the Apple logo is great for what it represents, the ecosystem is excellent, I still don't think a shrunk down iPad 2 with current technology (upgraded over the iPad 2 components) is enough for people to say, "I'll buy the iPad Mini instead of the much cheaper with higher resolution Nook or Kindle Fire HD." This won't be a cheap device.
What I think would be much more exciting and much more interesting would be a higher resolution iPad Mini with retina display that had all the latest technology bells and whistles on it, starting at £349 (I think that's the midpoint between an iPad 3 and iPod Touch entry models??). That to me makes a lot of sense, and that's a device in which I am greatly interested.