Before delivery, Car Play was near top of my list, but now I am wondering what I really meant when I said I would like Car Play and are there alternative ways Tesla can achieve it.
For rental cars, Car Play is great. We can get into any relatively newer rental car and don't need to worry about their native infotainment UI. Really useful. For a personal vehicle, for me personally, it comes to music apps and Waze. Have only had the Y for a week, but from what I can gather if we have Spotify Premium (and we do) the experience is great. But if it is some other music subscription, we go back a decade to using bluetooth. Same for maps. If we like the default maps, great. If we want something else like Waze, we have to deal with the ugliness of having a phone mount next to the giant display. Both issues would be solved if Tesla had an App Store and worked with popular music subscription & map vendors to add support. I am sure an app store can bring lot of other functionality as well but needs to be done in a controlled manner to avoid distracting driver (like Car Play does).
TL;DR My uninformed n00b opinion is that a Tesla App Store with pluggable maps would be awesome.