The reason for the particular sound you're talking about are simply aliasing (when pitch is shifted upwards) and a kind of sample rate reduction sound (when shifted down)... the waveforms are stored as single cycle waveforms, much like the old Waldorf Microwave synth, and it has that distinct sound to it... when the "sample" (it is basically a single cycle sample) is pitched down, the synth has to repeat certain samples more than once, and when playing higher it needs to remove some... unless the playback works like with the Modal 001, where the rate of the oscillator is increased or decreased to get other pitches... but even when you pitch down that way, you are still "stretching" the waveform, and if those waveforms back then were 8 or 12 bit, you'd get that raw, cold and grainy sound.
I actually like that sound for certain types of instruments, but I'd hate to only have that type of sound... it will mix well with other more beefy synths, and be good for nice synth sounds... I'd want a new modern version though... With a wavetable synth that has analog filters, and a way to bit reduce the samples to 8bit, you'd be right in the ballpark of this type of sound for sure. The joystick would be essential though as it's part of the performance... but there are MIDI controllers out there today that has joysticks... at least thumb joysticks... all the synth would need to have is four oscillators each with it's own waveform, and a modmatrix to route the two joystick parameters to the volumes of the four oscillators in the right combination... A Prophet 12 would be able to accomplish this easily I think, and with the right settings in hack and decimate in the P12's character section, you should be able to get that cold and sterile sound.
Now that I think of it, I'd actually rather have had a joystick on the P12, than those two sliders...