Or also, without! In a mobile device the principal focus should be in terms of software optimization because a bad design implies resource consumption in a normally more limited processor, memory and data storage due to the limitations in space. Furthermore the battery finishes sooner sometimes causing the complete uselessness of the device.
A virtual machine like Java usually means valuable processing time lost in exchange for benefits for programmers or other entities in the non user side
Some studies say about 40% less speed, others more or less in dependance of several factors in comparison with more low level languages. It's perhaps extremist to ask the programmers for the lowest level as any relevant change in processor architecture maybe makes all the code unusable. Not with more anticipation though! Higher languages also consume more memory and data storage space by definition and logic so any "smart" device should account with to not use longer paths when there's a shorter one, in a straight line without time consuming zigzags.
The front should be all screen, having the maximum screen size versus device height and width
Why to have two or three buttons in the bottom when these could be easily implemented in software as part of the main screen, tactile, and with the exact same functionality? The benefit seems obvious; it's when the user wants that space for having more usable screen. It's funny when the buttons are tactile and the screen looks a single piece but no, that valuable space is lost!
These portable devices are claiming loud for function keys!
It's incredible the lack of sense of whom design the devices forcing developers and users to use volume keys as function keys and with luck, because usually there's no mere option for this. The reality is full of applications and games that would encounter with function keys a much better user experience and possibilities. Plenty of space for being added, the problem stays in the conceptualization and efforts.
Better interaction with external devices. Internet by cable
Newly different companies with a friendly face toward clients are making strange movements for being with that level of friendship and coolness! In fact, the truth is more surprising and touching. Different smartphones have much more possibilities than the manufacturers or the operating system developers want to share or add. So the idea is to force users to not having them.
There are so many examples of this, from the configuration of the GPS toward the reality of "root" users, Internet by tunneling or whatever technique to continue showing logos, applications, promoting services or why not treating the user like a child without enough room for deciding if he or she wants to change the name of a system folder or making useful configurations.
Internet by cable, well engineered, goes better in stability and speed, and by far is more secure most of the time!
If you have for instance a laser printer for Windows, the smartphone doesn't know nor apply in terms of how to use it. Perhaps it needs a training course for being smarter!
No absurd limitations to configure the smartphone
The user could have a simple option menu to activate advanced configurations if they can be called that way, so no more “root”. With or without a message of warning, any problem must rely on the manufacturer as it happens with personal computers since the device should have protocols to permit the reinstallation of any software at the operating system level to run the device, allowing a complete restoration of the original functionality after any user action without a screwdriver. Making that root to gain extra privileges for your device, there's always the risk of "bricking" the device making it completely unusable. Well, this is another example of bad engineering and to charge those design issues to innocent users.
These upgrades are at hand, but let's mention other ideas floating around like foldable devices with the screen doubling the size of the device like a card folded in half. Or having batteries with a short waiting period to recharge and more capacity. With more bundled sensors to be aware of any electronically perceivable data acquisition. Detachable speakers coming from the device like extra ears for the landscape view with a coil-independent technology would be such improvement for media and room to high quality reproduction with more intense bass as the laws of physics dictate. With a solar panel to self-recharge?
More or less in the future... let's see!