I think that's a valid position to take, but people have different needs. Another person might say a mobile device should be big enough to let them use the non-mobile version of the web, or it should fit in their pocket. Or it should be light-weight# enough to comfortably hold in one hand for extended amounts of time, or it should fit in their pocket.

I think typing with ten fingers and the overall typing experience is surprisingly unimportant for many people.

# People have widely reported fatigue with the iPad (e.g. Ars). I don't know that the Google 7" device is any lighter, but I assume it is the case.