A few good ideas, to be sure, but I'm not sold. The iPad won't make reading PDFs any easier at the gaming table than a 10" net book - if anything things will still be shrunken down too much. Had they made the thing as big as apple's tablet-style laptops oh 5 years ago, this would be a slam dunk of a device. But at the size of a large iPhone, I really don't see this changing things all that much. Regarding laying the iPad flat and putting minis on it, in practicality being able to use a real - much larger - actual battlemat seems to be more useful for combat in rooms wider than 5 squares by 7 squares or so... (and if you're playing 3rd or 4th edition d&d, those scenarios will be rare at best...)
No native support for a camera or SD card for PDF's... That's kind of the piece that seals it for me. I like the idea of integrating technology with gaming - heck, that's the point of my blog - but this device seems like style over substance for me, as it relates to my hobby.