I think that Apple has pretty much written off the iPod Touch. Before the people buying iPod touches were ones who didn't want an iPhone because it wasn't available on their carrier, or because they couldn't justify spending the extra money on an iPhone for their kids because of the mandatory data plans etc, or their kids didn't need a phone etc.
Now they have the iPad which is becoming much more popular for younger kids because it is bigger and easier to hold on to, doesn't requirea data plan, etc. They also are keeping around the older model iPhones as a low cost alternative for people who can't afford the $200+ cost of buying the new model. The iPhone is available on most carriers now so that is no longer a reason not to get one. And with the new family share plans that the big carriers are forcing on people there isn't that much of a cost difference between having service on a smart phone or dumb phone anymore.
So really there isn't that much of a draw to an iPod Touch anymore. I can see them dropping it and having the Shuffle, Nano, iPhone and 2 sizes of iPad.