I will be excited to see thinner/lighter, but I'm not convinced that the Mini design is the right fit for the larger iPad. I'm not so sure i would want my iPad 4 to have minimal side bezels like the Mini. I think that works for the Mini because most people can hold it with one hand, but as I use my iPad I've paid attention to how I hold it and I almost always have fingers on the side bezels. I'd much rather my thumbs not be on the screen of my tablet and there's something really beautiful and solid-looking about the current large-ipad bezel.
Also the shape. I LOVE the shape with the curved back, rather than the flat back with slightly rounded edges of the Mini. Again, this works for the Mini, but I've found that when my iPad is lying on a desk or on my bed, it's very pleasant to let my fingers just scoop it up. Don't think it would feel quite so natural with the flattened Mini-style rear design. We'll see.