Well, curiosity got the better of me today, so I installed iOS 10 on my iPhone (a 6s model) and used Lightroom Mobile to save a few raw files so I could see what I could do with the phone camera if I had the original sensor data to work with in post.
I've attached four images: (1) a full iPhone frame, (2) a full frame of the same scene shot with a D800E (24-12mm f/4 Nikkor) to use as a control for whatever crud was in the air between me and the subject, (3) a full-resolution crop from the iPhone, and (4) a full-resolution crop from the D800E.
To the extent possible, I processed the raw data from both cameras similarly. I adjusted the tone curve to recover some shadow detail — I didn't try to do anything with the highlights because the overcast sky had very little texture — added a little contrast and clarity, and moderate sharpening. I used the color-picker to adjust the white balance from the hull of one of the boats in the foreground. The colors in the iPhone file looked a little off to me, so I added some vibrance and saturation. I did not use the dehaze slider since I figured the Nikon file was more useful as a reference without it.
I don't really have any observations about the result except to say that
- even with a raw file to work with, the iPhone (at least, not this model) can't match the image quality of a "real" camera;
- the iPhone clearly is more useful for an occasional grab shot with a raw file than an in-camera-produced JPEG.
But you probably knew that already, didn't you?