Hi sorry I took so long to come back to this thread.
In reference to the message from Konrad above. I am not a computer programmer so I don't know how it could work but if Notion can do it with Miroslav Philharmonik, Sibelius and Finale with various software I don't see why this would not be feasible for SONAR. Also I don't see this as a pure "classical composer" tool. It is more a question of having a music notation GUI to manipulate midi data. If it requires closer integration with the library why not do it with Dimension Pro. I strongly believe that the details in articulations, dynamics and tempos are more important than the quality of samples for realism. Proper orchestration is even more important. Not just for classical or cinematic stuff but for jazz, big bands, vocal arrangements. EDM is another story. IMO everything there is about sound texture, beat, ambiance, etc. I would like to venture into that eventually.
Another approach would be similar to VST Expession maps in the Cubase world. I never used it but from demos on You Tube it looks interesting.