I highly highly doubt there will be a native turn-by-turn navigation app in the update. The reason being for that it would need to store a large amount of data on your phone rather than downloading new maps all the time as it currently does. You need the maps locally for when you go off route for it to recalculate in a timely manner. Just imagine how long it would take if it had to download more maps (assuming you had a 3G signal) and to recalculate. It would likely take more time than most are willing to wait for. I find it likely they will upgrade the GPS software so it can support turn-by-turn nav. I believe I read TomTom was working on a turn-by-turn solution for the iPhone a bit ago. I can see a company making a separate program that can be downloaded (optionally, and for a fee) to allow true nav functionality. This would likely take up at least 1gb of space on the device as well for a halfway decent setup of the US... then again they could release it via region and have split the country up into various packs. Who knows...
I have also read Copy/Paste will likely be included. Beyond that it is anyone's guess.