A remote interface of my phone on the touch screen would unleash so much more potential than we'll ever actually see from in-house development or even "selected 3rd party" development. Tesla has done a great job of trying to push the limits compared to what any other car company is doing for built-in tech features. That said, it's still miles away from what everyone wants.
Let's face it, my phone has a newer version of google maps with newer features than my car. For that matter, it also has a newer version of navigon too. That's not even touching things like waze or a myrid other apps that will never be ported over to tesla specific versions.
I'm not even talking about all the really cool stuff that would be possible if an app could communicate with the car, I'm just talking about things the phone can do all by itself right now. Just mirror the phone/tablet screen onto the 17" screen (or even half of it) and you've increased the usefulness of it by a couple orders of magnatude. If you could relay touch events back to the device as well, you'll have redefined the dashboard as surely as tesla is challenging ICE vehicles. (yes, I realize that part is non-trivial.) Run the whole thing in a sandbox with no communication to the actual vehicle systems, and the worst malware is going to do is make you replace your phone.
And then all the tesla software folks can focus on car-specific features and not spend time making mash-ups of old versions of navigon and google maps.
... and then everyone lived happily ever after. the end. (sadly, it's unlikely to happen though.)