This is exactly the kind of innovation that Apple needs! Oh, wait...
I completely disagree. For an iPad, it's all about its weight. If a 13" iPad weighed the same as a 10" iPad, it would completely replace it, because a bigger screen is simply better, and there's no loss in portability between something the size of a half sheet of paper and a full sheet of paper. (If you can carry one, you can carry the other.)
But the weight is critical, because if you have to sit it on a desk because you can't hold it long term, then the extra screen size it totally wasted.
When SJ made the iPad, he felt it was the SMALLEST that was practical. Could he have made the original larger and kept it light weight and affordable, he would have. It was also under SJ that we had 3 sizes of Macbook Pro, and I feel the same about those - bigger is better if you can make it light.