Does their face became the active user? Does the Facetime call continue on the TV or does it just get shunted to your iPhone in case you won't be right back? Do you employ multiple microphones to filter out home sounds so your voice come through clear? Where would these multiple microphones be housed? I'm pretty sure they thought of and rejected the simple add-on when they realized it would be a suboptimal solution that upon trying most consumers would react, 'Yeah but I wish.'Remember Apple is a company that prides itself on thinking of scenarios you didn't even know you had and design a product for that. Do you try to zoom on the users face or do you use a wider shot that might show more of your home than you want? Do you include facial recognition to ensure it stays zoomed on your face and not on your child who comes wandering into view? What happens if you get up and go to the kitchen, but someone else is on the couch. I thought about putting something like a U1 chip in the Siri remote so that whoever is closest to the remote would be considered the active user (in a multiple iPhone household) so that their calls appear onscreen but I imagine that is kludgy.While dreaming of a camera attachment that connects to the ATV is a wish for some, trying to optimize for the different distances of seat to TV could be a problem (unlike webcams and selfie cams on phones). Our iPhones/iPads are personal devices but the ATV really isn't.

How to airplay from mac facetime