Let me add, that patcher systems make very good "glue" environments Take something like VASP: It's a huge, C++ library, which in the end is glued together by Pd. So Pd lets developers more or less ignore GUI stuff or DAC/ADC interfacing, because that's what Pd does for them.
Well, i have done a number of projects using VASP lately and i have come to the conclusion that the patcher-oriented programming is rather a pain for these kind of things. In fact, the next generation of VASP will be a C++ library alternatively steered by scripting (Python or Ruby) and external objects.
best greetings, Thomas