What could they do to make it better? Make it lighter? How?
There are already people saying that it doesn't do enough because Apple wanted to hit that weight and ergonomic factor. Make it thinner and lighter and you lose even more.
Make it thicker and chunkier for big hands and it gets too bulky to be that goto option over a laptop.
Put it in an agenda style wallet and you turn a lot of people off. I know I don't like these Wallet style cases. They've been around for ages on various phones and pda's and never really seem popular outside of the US. It's a style that I don't like or get. So the iPad ships naked to allow people of varying tastes to make their own choice.
Reading through this thread it is clear that some people want something that is smaller and lighter. And Apple already make that option - the iPod and iPhone. The iPad is aimed at people who want that, supersized.
I agree that holding it in one, or two hands, unsupported, it gets a little heavy and uncomfortable. But I don't think that's how they envisioned people would use it. Me, I sit on the couch, cross a leg, and support it between my waist and thigh, holding it lightly with my left had whilst my body takes the weight. Slouching helps, for those of you not overly concerned with posture. Or I half lay down in bed and rest it on my stomache, whilst supporting it lightly with my left hand. Or I scoot my knees up in bed and lean it unsupported on my thighs. It takes less effort, and feels way more comfortable, than attempting the same sort of thing with a laptop. Reading this back, I could be taking about my manhood, really, I am talking purely about the iPad.
Personally, I think Apple nailed the ergonomics. Maybe they coulda saved a few grams by using a thin iPhone like rear casing instead of the Aluminium, but really, I prefer that feeling of solidity.