It looks pretty, but I hope they move the power button to, well, anywhere other that directly across from the volume buttons. It's wonderfully symmetrical design, sure, but two years on, and I still occasionally line up a great one-chance-to-capture-it photo opportunity, and... turn off the display, locking the phone (because I pressed the wrong side - which is either the top or bottom depending on which way I've happened to rotate the phone to reach landscape mode - or squeezed the phone between thumb and finger and the power button "won" over the volume button). And by the time I can get the phone back on and unlocked and the scene reframed, the child or cat or whatever has wandered off or stopped having that expression and I've lost that photo opportunity. This was clearly a case of form winning out over function and usability.
This won't be a popular request, but I'd also love to see them add a play/pause button between the volume up/down, in line with what the iPods have. There are numerous times that I have the phone in my hand, and I'm listening to music or a podcast as well as using some app, and I have a sudden need to have the phone stop making noise right now. Someone asks a question or something. And suddenly it's a mad scramble to pull up the control panel and swipe to the music tab and then press pause. That seems like such a poor hack. If they want me to consider it as a music player (that was, after all, one of Steve's original three pillars of the iPhone), being able to directly pause the music is a pretty basic expectation. It'd be a boon for AirPods users as well.