So, what I'm asking is what would you like to see changed or improved about the functionality of the iMS-20?
Here's a few small ones to get the ball rolling:
1. Double tap on a control to return it to its default setting. (They've already got double tap on the control or patch panel to zoom to that section and double tap to zoom out - just add double tap on a control to take say, the LPF cutoff to 10 or the HPF cutoff to zero, or whatever the INIT value is for each control.)
2. A fine entry mode for the controls. (ATM they are all stepped, mainly in units of 0.8. I'd like to be able to go in units of 0.1 for all controls, as I'm sick of the fact you can't set units of semitones accurately for the Osc 2 pitch control, and the way the MG Frequency is either a little too fast or a little too slow, with no in between, etc. Just add a button in that blank bit where it says Voltage Controlled Amplifier to momentarily toggle fine entry mode.)
3. Fully variable gate length in the sequencer. (Not just 0%, 25%, 50%, 75%, 100%, and Legato.)
All of these would be easy to implement; now for some harder ones:
4. An extra input jack in the Patch Panel for control of the Osc 1 Pulse Width knob, so you can get Pulse Width Modulation (PWM). (OK, you can fake PWM with the sequencer, but it's not convincing, and it was a common mod to real MS-20's - it's bizarre it was left out in the first place. I can't see them doing it since it would destroy the supposed "authenticity" of the synth - like the original had KAOSS pads.

5. A set of "many to one" and "one to many" multiples for the patch bay. (a "many to one" multiple lets you produce a single combined control output from several input sources - say, combine EG1 + EG2 Rev Out so you can send them both into the LPF Cutoff input; a "one to many" does the opposite: it lets you take one control output - say, the square wave MG - and send it to several different control inputs. Again, this was a common mod to the original MS-20 , normally as a separate box, since there's not room for it on the original panel.)
6. Add a pitch entry mode to the drum synth so it can be used as 6 separate pitched & sequenced monosynths, not just for un-pitched sounds like drums. (I'm probably asking for too much on this one, but if you don't ask, you don't get.

OK, that's some of mine - what would you like?