13" Macbook = 4.7lbs
iPad = 1.5lbs
I'd say 3 x less weight, but 1/3 less computing power. Do most of us need that 2/3 ever single day - I'd argue not,.......................mostly.
That's the thing. I reckon most computers have way more capacity than we need and the phones are leading the new direction.
What do we normally do on our computers? I'd say most users surf the web, write the odd document, use it to listen to music, download+edit photos, maybe pay bills and watch films. And you play games.
You pay bills once every now and then. Same with writing documents and editing pictures. No big need. What's left is not much, so you can have a fairly limited capacity. Play a lot of games? Buy an X-box or PS3. Capacity needs goes down even more.
This could be the device, but I'm not sure about the size, nor the way of typing. If either is just slightly annoying, I reckon it will fail as a product.