I don't think you know how streaming works.
Three options
1.Playing only on TV,controller screen is off...just like "normal" consoles
2.Dual screens,like controller displaying menus,map...think DS
3.Same as number one,but controller is the screen
no no those three options contradict each other
Playing on TV or playing only on controller screen - ok
Dual screens - ok
Both - what
"Controller is the screen" means games can't be designed around dual screens. likewise, if you have a game that uses touch when playing on the controller, how do you have that if you play on TV. They'd need two or three different interfaces for each game for it to make sense. But that'd then you can't design a game to take advantage of dual screens or touch screen.
They don't have to be,that's the beauty of this.Although Nintendo will surely try to that...DS copy-paste
Lets take some hardcore game designed around dual analogs
Option A...controller is the screen,no touch controls no nothing,controller screen is like hooking another TV and playing on it
Option B...controller is used as something else(weapons select,map,etc),touch controls,dev intervention($$$) needed
Third party will prefer option A
The only problem is that it has to be streamlined,working with every game,handled by the OS,minimum user and dev ($$$)input needed.
System can be one big DS if some dev wants that...this is not 3D
