No that's not the point I was making. I was saying that to make a good delay in software it can't just be a delay. To sound good, it needs additional algorithms to carry out at least 2 other DSP functions on the return signal.
Yes that's a good delay filter but it's also a good example why this type of user-programmable synth apparatus, which looks similar to CSound, won't catch on. There is much more going on in the typical delay sound itself than just a delayed iteration of a sample. A pure delay is boring. There is the possibility to model all kinds of analog and hardware digital delays with additional coding, but people have been doing that for years and it's no surprise really that commercial companies do it best (and they won't bother unless there's a way to protect proprietary code such as VST).
PD and Max-MSP are from the same stable, and PD is the poor man's Max-MSP. I feel that PD is an excellent learning tool if you want to learn about synthesis or DSP more generally, but as a musician's tool it's just not ready. A lot of the music made with PD is pure crap, or even a type of anti-music, or puts forward some kind of alternate musical theory of its own which nobody can understand. PD music is usually too detached from normal conventions such as 12 TET, harmonies and progressions to be listenable. Typically the PD user will produce something with weird bell sounds, stuttering percussive noises or massive pad washes going in and out. Not conventional music. The reason is that PD doesn't provide enough built-in function shortcuts. If you want to make music, PD is a practically useless interface. By the time you've programmed a very basic synth, any inspiration has long gone. An instrument is something that should need no foreplay beyond just turning it on and picking it up, before actually playing it. If you want to make something recognizable as music with PD, you will need to first download someone else's synth patch or copy a subtractive or FM synth from a book first. And then you'll find it has no patches you can modify (unless you make them yourself). The time between turning on the computer, setting up your synth and playing your piece is simply too long.