Not true any longer, at least for the binary packages I produce[0]. I switched them over to trunk-based builds a while ago, which are updated every few days.
Thanks. I had to look back at my notes. I had issues with matplotlib and few other packages at the time with python 3.4, due to python not being built as framework.
I have just found a related issue: https://github.com/joyent/pkgsrc/issues/331 Unfortunately, from what I read there, I have still to use homebrew or install from python.org (with those I have no issue). I really enjoyed pkgin otherwise.