Then Nokia should lead. Continue to nourish and grow the tablet device instead of being lead by the nose based on iPhone sales success.

Even Apple knows that the iPhone is a "one trick pony" and is busy developing, and soon will release their new tablet device (or "taplet" as the press is now calling it).

Nokia found the sweet spot with device size (pocket-able), display size and resolution (aging population), and battery life.
For the North American and subsidized handset markets they should continue improvements in BT, WiFi, WiMAX, and other non-cell connectivity with the tablets (including mesh networking schemes).

The should also develop low cost, small BT and WiFi tether-able non-smart phones for this market that customers will want and carriers can subsidize @ sub $99 sign up prices.

Again, I'm thinkin' that the iPhone is like the color ink jet printer when it first became viable in the market place. Everybody had to have one in their home. All-in-one scanner, printer, fax machines also became all the rage much like a do it all "smart phone"...

Eventually the market figured out that they were paying a premium for color ink jet cartridges in order to have the ability to create faded color birthday cards and bogus certificates of achievement every once in a while (kind of like a new $10 a month iTunes bill just so you can be sure to have the latest iFart app). The novelty and attraction ended for the public as soon as everybody had a color laser jet.

In the end the market went with small, efficient, purpose built, separate components.