Instead of moving towards smaller devices, the mobile market has somehow been forced towards high end, multi core, power and bandwidth hungry, gaming type devices. Users seem to be drawn towards the multimedia and social media capabilities..... The future development of mobiles will possibly be depicted by demand.
Expect the next big gadget to be Augmented Reality glasses that make the phones obsolete in many markets. You'll get real-time translation when you speak to a Chinese or Mexican person, real-time info about everything from stores/traffic/electronics/food/medicine/you name it, a virtual personal shopper or maybe cook food in your own kitchen with Gordon Ramsey? There are so many possibilities and so much cash people will make on so many things in this area that it just will happen.

And for the end users, you just put your glasses on and there's a new world out there. Your kids can drop the iPad and instead go for "dinosaur hunt" in the forest. These new gadgets will of course come with completely new demands on mobile networks. The networks have to be faster, more responsive and with less variety in quality and coverage. You don't want your glasses to stop working anywhere. For me, 5G is about securing the user experience on these devices when they arrive some years from now.
The growing physical screen requirements for gaming, video and social media and bulky batteries are the immediate challenge. The augmented reality glasses (or a contact lens in the future) will solve the screen issue - and vastly improve it. Whether it is nanotech, or micro computers, the future energy requirements for these systems will diminish greatly. The power source is going to be a one of the biggest issues in the next 15 years to making the phone "disappear" and go virtual. The smartphone as we know it today will disappear and become an intuitive, responsive, likely wearable solution. Some futurists talk about implanted technology, but this is not viable in an environment where technology is advancing and changing so rapidly.
Evolution brings technology further that’s true. But the new coming technology will apply to early adaptors and not to the middle aged user and beyond. Most of people today will regard this as a completely unnecessary gizmo in terms of usability in their art of profession. It´s a market there for devoted people in generation X. Never the less development of technology will strive to a new way of communication for all of us. But it will require some time to adapt to technology. It will be stunning to follow in the next coming 5 years. 
Microsoft Hololens and other first generation AR devices won't be a mass-market product. But the difference between a pair of sleek glasses that you will get in the longer perspective and something like a watch is that while the watch really is a gadget that doesn't give you much extra value over a phone, the glasses will provide so much more since they are places in front of your eyes. Just imagine all the information you could get. Google or someone else identifies what you look at, and if you want you get instant information about the object which could be a bus, a building, a road, a complex technical/medical situation, an equation, a product, food or whatever you want. This is not something "cool" like a watch, it's extremely useful information and you have access to it all the time no matter if you're walking, driving or running.
I have read a fair bit on this topic and people talk about transformations of industries. There might of course be other gadgets that also are very useful that people go for, but the AR stuff will take off. It makes so much sense and everyone wants them when they reach the right shape and functionality.
Revolution will not come from a change of interface i.e. phone screen vs. glasses or implanted technology. The revolution will come when we move from a digital corporate tyranny to a digital democracy.

As more and more IoT devices get into the market, the value we create simply by living our life is constantly increasing, let`s take control over our devices, what they produce and share and let`s start benefiting from it.

The revolution will come from direct interaction between on the net peoples (their digital representation) and objects without data hoarder middleman. Revolution will come when people take ownership of all the data they produce and have the option of monetizing or sharing it on their terms. When I come home, my phone or whatever technology representing my digital self on the net, should be able to communicate directly with my house and take the actions I programmed them to do without a Google or other central corporate platform being aware of anything. I don`t see why anybody should know for free that in winter I like my house to be at 22C, only because I want the convenience of managing my thermostat based on my location or through my phone. Why can`t I simply access my thermostat directly? When I physically turn the knob on my thermostat nobody else is aware of it, why should it be different because I turn the knob from my phone?

Since I am a good citizen and believe that some of my data can contribute to improving my utilities quality of services (and therefore the quality of life of my entire neighbourhood or city), I accept to sell some information to the utility in exchange of a discount on my bill. I am helping them improve their bottom line in exchange they give me a discount based on the type and amount of information I am willing to share with them.
Data Routed Cellular Communication Apps that work on iPod and other similar devices that are not phones but have an internet connection - thereby turning the non- phone devise into a 'phone' already Exist. The digital revolution is all taking place via software, up and down the stack – from new database technologies, through new operating systems, all the way up to the apps, which are mostly the tip of the software iceberg that the carriers are crashing into.
If scientist get their way nano technology may tilt the scales towards mobile devices streaming more data. As the United States play catch up with the rest of the world in data speeds it open the doors to so many possibilities such as AT&T announcing that in five years they will be giving up all copper line and going with all fiber infrastructure. The end game is this eventually technology will continue to advance increasing in bandwidth computing power and storage capacity. These are the biggest three factors in communication that will dominate human perception of technology.
In Sweden they are more or less getting rid of copper wires. The field is open for high transition data more or less to any device. I can see a market field that slowly but surely out competes legacy PBX to form into something more cloud enabled. It will be a major change in the telecom business for years to come. Old rules will fade out and be replaced with new communication policies among companies. But I would say that it will have the same touch and feel like ten years ago when everything turned into IP. In Sweden hasn’t seen a fantastic movement to true unified communication solutions yet. The customers are not yet ready to go "all in" on front edge technology and to implement. But the race has started and I would guess that the Gismo glasses and other things will be put into action far sooner than IP Telephony 15 years back in time. 
British Telecom aims to shut down traditional phone network to help it battle US tech giants. BT is calling on the communications watchdog to let it scrap the traditional telephone network, as part of a campaign to loosen regulations that it says will help telecoms companies compete better with US internet companies such as Apple and Facebook. The telecoms giant is planning to move all domestic and business customers to internet-based voice calls within a decade, but under current Ofcom rules must continue to provide a traditional phone service.
To look forward from the present is incredibly hard, if not impossible. But if you have enough foresight, you can put together pieces of an incredibly complex puzzle to get an idea of what the future might hold. To do that you need to look far and wide at available technologies. You also need to look at research projects, scientific experiments, prototypes and patent ideas. And more than anything, you need to think about the benefits future technologies will provide.
To think about the future of mobile technology, you need to consider that the phone is just a medium of communication. At the core of the phone — email, WhatsApp, Viber, SnapChat, Twitter, etc — is simple human-to-human communication. And the evolution and revolution of mobile devices over the years always comes back to one question: How can we make this easier and more efficient?