A wind controller that has breath control, but like an open-holed flute or pennywhistle except instead of open holes there is a pad of some kind with pressure and aftertouch for expression/pitch control/glissando between notes. A simple-system flute, in other words, with end-blown mouthpiece and really simple fingering like a pennywhistle. The thumb would be for global key change (it is not well-tempered) and octave shifts or a more extensive portamento. The effect would sound like a pennywhistle being played expressively. Of course it could then be applied to any other sound in the sound module.
This would be great for recording music with lots of expression being applied in real time by the player's fingers, instead of applying expression later in a DAW.