Who said the pro would be just a larger iPad? I just finished describing what a pro "could" be. An iPad 4 is perfectly up to the tasks I could ask it to do. The lighter weight and more power is just a minor benefit to me. I've got my iphone for ultimate portability. Give me a device that will do what my desktop and laptop can do combined with the UI of iPad and do it in a way I haven't done before, I'm in.
I only read the attached keyboard bit. It will need a lot more than that to be more productive. I agree with the bolder statement above. I have a MacBook Air and imagine what a fully functional tablet (an iPad with the soul of a MacBook) could do. I'd buy it too.