Smartphone cameras are simply amazing nowadays. Have a look at the picture above, a Galaxy S7 doing its thing. The S7 and its Edged brethren are currently at the top of the heap in regards to smartphone cameras, according to DxOMark. The HTC 10's camera, using HTC's Ultrapixel gambit, joins them at the top. Just a couple of years ago, these kinds of photos would have required a dedicated camera with all sorts of bells and whistles, with most models costing upwards of $1,000.
More and more smartphones these days are pushing to integrate more features and experiment with the camera to optimize things. The LG G5, for example, sports dual cameras. Although that fell flat, Samsung pushing the envelope with the S7's camera by making the lens a show-stopping f/1.7 aperture, letting in far more light than the average camera and using software optimizations to avoid common issues that come with that, like excessive shadows or blurring. While many gimmicks and extra features like this may make little difference or fall flat, that may be the direction that smartphone cameras are heading.
The Galaxy S7's camera is the gold standard in this metric, pretty much representing the best a camera of its size can do. The aperture is tight, the software is great, the megapixel count is more than sufficiently high and the sensor itself is top-notch. Without extra cameras to change focus, optical zoom or a larger space to put the camera hardware, this is basically as good as things are going to get. While a larger lens is, of course, an option, it would make phones thicker, heavier and, perhaps most importantly, more expensive. In a time when devices are getting thinner, lighter and cheaper at an alarming rate and finally beginning to break into previously untapped markets, taking a step back in these areas would be disastrous. A wider lens would allow for more hardware to be squeezed in, more light to get in, even at higher aperture spacing, and even room for hardware that could support postprocessing, but would it all be worth it?
Some of the extra features and gimmicks that future phones could come with would be things like optical zoom, extra lasers for autofocusing and, of course, far better software as we go further into the future. Unless some sort of breakthrough in light refraction technology allows the development of a smaller camera with all of the properties of a larger one, this is the direction that smartphone cameras will have to go, with the exception of dedicated, camera-focused devices. Companies like Light.co and Lytro are working on things that may allow smartphone cameras to get even better, such as sensors that support after-shot focusing, and multiple lenses packed into a smartphone body that can be switched out on the fly for better pictures by fitting the lens to the situation. Innovations like this will likely rule the roost in the future, as well as optimizations, reiterations and small improvements and tweaks on current designs and features.
One feature that may get a boost is laser-assisted autofocusing, along with its cousin, optical image stabilization via laser. Laser technology and sensor technology in phones are both improving by the day, leading to the possibility of insane levels of focus being attainable in less than a second and not being disturbed unless the user deliberately changes the target. Pair that with A.I. developments that would allow future camera software to choose a target and get a fix on it and, for all intents and purposes, there will never be an out-of-focus smartphone photo again once these systems are improved and integrated. Another feature would be multiple cameras or lenses; while the HTC Evo 3D and LG G5 most famously played with this idea, the uses for such a thing beyond postprocessing and bokeh are quite vast. Multiple lenses could simultaneously capture an image and then process it into what an A.I. determines to be the best configuration before presenting it to a user for normal post-processing. Pictures could be shot in extremely short sequence by the multiple lenses to stamp out motion blur by juxtaposing the pictures to figure out what's noise and what's OK to include in the final image. These are, of course, only a few of the ways smartphone cameras can improve, but as for raw specs, we've pretty much reached the proverbial event horizon, here.