Pyramix is Audio-only with its own Plug-In Algorithms but can also load VST. That's not the matter of fact, sure. Samplitude on the other hand is Audio/MIDI. I've used the last one with Sample Libraries and VIs. These times are gone, because I wanted the Windows-Part on my Mac Book to be audio-only.
But you're probably right and it's a good idea to split those libraries out. Otherwise:
