Ok, I'm start to thinking how make a ergonomic mockup. So, I try to understand the standard format of current controls. They basic idea is 2 analogic, 1 dpad and 4 front buttons, with a curvature, like that:
That curvature is necessary to maintain the comfort for long playtimes in one of the 3 ways you need to hold the control:
Two hands in the 2 analogics. Most used for full 3D games.
One hand in one analogic and other hand in the buttons.
One hand in the Dpad and other in the buttons. The classic mode.
Most of the games you fix your hand in one of these 3 positions. You can push the others buttons but most of the time your hand will be fixed in that.
Now lets look at 3DS design:
They put the Apad and Dpad in line, but don't do the same on the other site, because they know it will make it bad to hold.
The truth is that, in a portable, the upper part in the best to put the buttons or analogic and the lower is a bad choice.
Sony try to make a tradicional desing with vita, but in the end, the small analogics don't help for long play times.
So, the best we can have in a portable, is put the main buttons or analogic in the upper part. But since it can chance for each game you play, how they can do that?
Simple:
and
The curvature to use different ways is not necessary if you ca always chance the main buttons or pads. Problem solved.