There's no real reason to consider csound any different from any other synthesiser in this respect: someone who understands how to program a synth just needs to know "which knobs and switches" there are - whether they're physical hardware, a virtual instrument's GUI, or xml statements doesn't matter all that much... the only thing that matters is being able to set and control VFOs/LFOs, ADSR, resonance, unison, etc. =)

And dear lord do some people understand synths.