Offline functionality...
But did they include the obvious offline navigation functionality?
When abroad, I want to download navigation information and use it offline in the rental car with some leeway: The device should allow me to turn off the selected route (for a break, for a restaurant, for fun, or to avoid that new construction site), and it should remember some alternate routes in, let's say a 30 km strip around the main route, remember alternative major roads and highways in a larger area (let's say a 100 km strip around the chosen route) -- so I don't get an irreversible blank screen of death just when I need the navigation system most.
It's a no-brainer, but I guess the developers are too brainy for that.