I would like to see Frequency Modulator included, something like Holger Czukay used a lot for CAN recordings. I read somewhere Holger took that original unit from Stockhausen studio and used it thru years on guitars, voices etc... Super robotic sound, much more interesting than ring modulator for me. Also, early Moogs had something similar...
I don't know, I'm not an engineer so let's leave the tech side for experienced people if it's a matter of the special circuit or completely different kind of effect, but that particular sound would be nice to have.
Also, Holger has something like a RADIO modulator:
"The radio has a VFO – an oscillator – where you can receive single side-bands, which means just half of the waves and you can decode it – it’s like a ring modulator. And that’s more than enough. The other members of Can were very open to these unpredictable uses of instruments, especially in the early days."
So something in this direction would be nice. Everybody is tired of "normal" flange, phase, ring mod. Let's get something really unique for our future records : )