Re: GSoC for Purr Data, I just want to say
1. That's great news! Congratulations!
2. I saw the list, and while I'm sure some internal improvements would be good, for me, plugin integration would make a huge difference.
VST has unfortunately been completely removed from Csound in response to Steinberg's aggressive approach, old CPS seems not to work anymore, and yes, PD's plugin possibilities are unstable. There are Distrho PF and iPlug2 and Faust, but none of these allow hosting, only being hosted. Other than that, to write software that hosts as well as plugs VST, it's Juce or Steinberg's SDK.
A few years ago, it seemed like this functionality was cropping up everywhere. Today it has disappeared. I for one would be thrilled to see this happen.