This is a very interesting one - it reminds me of something a Nokia representative (probably Ari Jaaksi, but I could be wrong) said when they launched the 770: that the very reason for this product line is to create a new kind of device, a whole new market. Something thats not a media player, not a PDA, not a phone, simply not something we already know but the first of its kind.
Thinking of it, it makes sense that Nokia tries so hard to avoid anything that could possibly put the tablets in one of the existing categories in public perception:
They dont want it to be a PDA, so they dont offer even basic PIM-functionality (even though Nokia has this kind of software)
They dont want it to be a media player, so they dont offer high capacity storage (even though it would be possible with only minor changes to the design)
They dont want it to be a phone, so no SIM-card.
I never thought of it this way before... So they're doing something very, very risky with the tablets. You're right: people tend to buy devices for well known concepts. Media player is a well known concept. Internet tablet isnt. So what Nokia needs to do is slowly make the concept known and create the market with as little risk as possible - because it could fail miserably.
I feel they've been successful so far. They wouldnt have introduced a third tablet if the 770 and N800 wouldnt have met their expectations sales-wise. And, even more important, other manufacturers join the party now. (Think of Intel.) Still, the game is not over; we'll yet have to see if the market actually exists in 2-3 years.
One more reason to keep it simple and not waste precious space. Yep, seen the previews. Guess I'm simply not the Apple kind of guy. I remember when first working with OSX the dock made me scream and shout because I didnt find anything there. And Apple-guys say its the best since they invented chocolate. Will probably be the same for this concept...