Ipad 5 release mid October.
2014, 12" iPad, facial, head and upper body gesturing.
Use your upper body for modulation, pitch-bend, volume, expression, effects depth, etc.
2016, 16" iPad, initial velocity and pressure sensitive and voice effects recognition.
2018, 20" iPad perfect speech recognition. USB ports.
2024 60" iPad folding down to the size of a 10" iPad.
I wonder why Wacom (or any of their competitors) did not pick up the ball and make a Cintiq for digital music. http://www.wacom.com/us/en/creative/cintiq-22-hd-touch Ok it is rather expensive but some musicians will pay for such an instrument.