Well there's plenty left to put in that will allow them to have an iPad Ultra, with extra thin absorbent layer with wings.
I think some of the criticism is a bit melodramatic, it's certainly opens up new avenues. The screen real estate allows the micro-application phenomenon to continue but with bigger, better and more functional applications coming to head.
But then it misses some of the digital next generation bits badly (no doubt to come in iPad 2.0). An integrated phone while it has GSM/3G connection is a bit daft, was there mention of GPS? No camera. So it starts to become another non-unified device again. Augmented reality is one of the biggest next gen booms, but I suppose civilisation might wait another couple of years for it to really take off.
So it's going to be locked down like a motherfucker, which is its biggest flaw, but biggest asset, in my opinion. There has to be some middle ground at sometime. Thing is, as much as some folk are saying it's a big iPhone, make no mistake about the engineering of the device - it is immense. I'd be very surprised if another manufacturer is able to follow suit in the next 12 months at that price point. Or, maybe they'll just wait to see what the uptake of a tablet is. Personally I think tablets are the future.