Ronin1973 - I agree with you completely in your description of complex waveform generation.
However, I interpret the name "Complex Oscillator" - with a capital C and O - to be very specific. I assume (humbly), and have always been of the understanding that this term specifically refers to the methods of creating complex waveshapes in the method employed by Don Buchla with his Buchla 259 Complex Oscillator.
photo here: https://modularsynthesis.com/roman/buchla259/259_cwg.jpg
Technically - the creation of a waveform using a basic FM schema of modulator and carrier, with further adjustments using symmetry and wavefolding. As opposed to say phase modulation, multi-operator FM, wavetable synthesis, etc...
I like the tradition and challenges that come with it.
Rubicon2 is a perfect example of the carrier part of this - add a modulator of your choice. Love that it's through-zero.
Even Buchla have evolved their Complex Oscillator - their newer module, 259e Twisted Waveform Generator is digital, and uses bits of of it's own operating code to create wavetables to use as it's modulator! Wish they had a Eurorack version! Probably the closest module we have to this is the Hertz Donut MkIII.
Great statement - "What brush would you like to paint with?" ...well said!