This is an awesome design.
I would certainly buy it because I am looking especially for some MPC I could just throw into my backpack. I also have some notes to probably make it even more HH
Bring the control buttons up between the pads and the display and loose the rotaries next to the screen. That way you could make it slimmer so it is symmetrical on both sides and can be played with both thumbs while holding it in both hands. I would bring the controls up because if you bring them down below the pads you might trigger them with your palms by accident
For the q-links (I dunno how they are called but those with horizontal disks like in old pocket radios ... or some fancy modern touch controls that can be operated by sliding you finger over them and they should work in relative mode so you do not have param jumps): You could add 4 in the "right view" that could be operated with the index finger. Or two in the left view and two in the right view at display's height. So you could use both index fingers to operate them. Would make operation quite natural imho since I think you hold it that way anyway: Thumbs on the pads, index fingers stabilising on the sides and the other finger holding from the bottom ... hell you could even add some buttons at the bottom. I wonder why nobody has done that yet anyway. Feels so natural.