Optical zoom
It seems every phone can take great shots these days if you don't want to zoom, and have good lighting.
Lighting is being resolved through clever tricks but I still can't take a photo of anything not right in front of me, in most cases. Granted a phone isn't a DLSR but my Lumia 1020 had proper optics.
My question is, can one buy an after-market clip-on optic to get 5X zoom? Don't laugh, but in the past I've stuck my phone up to the eyepiece of my binoculars and been really quite surprised how well it worked, letting me take photos of a bunny across a field or whatever.