This thing
Lets talk about it.
It seems some gamers, media, and developers alike are confused by this thing; its a new gaming input revolution and I am here to tell you why! :D
Gaming inputs have changed a world over since the old nobs, sliders, and oversized joy sticks. The first big change was the D-pad, this replaced the industry standard large joysticks. Then came the standardization of a 4 face button array (a number that made sense to your thumbs). Then the shoulder buttons (finally getting those index fingers some proper use). Then the almighty dual analog sticks (savior of 3-D gameplay).
You might be wondering why I stopped there. Simple, every other input ALTERNATIVE since, has been used as a replacement of one of these other inputs. Their functionality may differ, but the implementation in gameplay had to be an "us or them" situation.
This is where the back touch panel says, "Good news, we can finally play together".
Some of you might be confused right now, thinking "didn't this already happen on the DS?". The answer is not quite, let me explain why.
When using a front touch screen, a player is forced to remove one of their hands from the other inputs. Essentially this breaks a player away from the current form of gameplay.
Simply put, the front touch screen in this case (though functionally different) has displaced the use of 4 face buttons and 1 shoulder button when in use. This limits what a play could previously do and offers an alternative when in use. This is the "us or them" scenario in play. In game design, this requires a slower pace of gameplay or alternate piece of gameplay to be an effective use of the front touch screen. Otherwise, it simply handicaps a player's range of inputs during use.
So now, why the back touch panel will revolutionize gaming inputs as we know it.
First, the obvious and less important point, the back touch panel can be used for effectively being a mirror to the front touch screen without obscuring your vision when you use it (or smudging it :P ). This inherently gives you access to (if game designers choose this route) all of the gameplay innovations that the front touch screen has brought us in the past 7 years.
The true advantage (and advancement to gameplay) is that you can actually use the touch panel with your middle fingers, while simultaneously using your index fingers on the shoulder triggers, while simultaneously using your thumbs on any of the front inputs (This would be impossible to do with just a touch screen). That allows an immense multitude of button inputs to be combined with back touch inputs to allow for a massive more dynamic range of design of player commands.
3 dimensional gamespace example: To be able to use the left stick to move the character, while using the right stick to move the camera, and using the back touch panel to target anywhere in the present field of view (without additional movement of the camera), then using the L or R trigger to issue an action command (such as shooting, or sending a minion after said target). This is fluid and quick in execution, because it never removes the player hand from any of the control inputs.
2 dimensional gamespace example: To be able to use the d-pad to move, while jumping with X, while holding right stick to trigger a quick skill from a skill wheel, and using the back touch to both target and execute skill with 1 touch. This would allow 8 different skills to be used accurately, easily, and on the fly while playing a 2-D Platformer (while not using up any other dedicated button commands).
There are thousands more combinations that can be tailored to each game's specific gameplay genre/scenario. This all expands gameplay possibilities quite significantly, when you properly understand the theory behind combining these inputs for fluid, quick, customized gameplay.
