I would dare say that most of the people here (and other orchestral lib users) no longer use VSL for 'mock ups'... but rather as the end product. Therefore the most 'life like' results are of paramount importance. If you hear a really decent VSL rendering it's 100% sure that the source MIDI would bear only a passing resemblance to the notation one would give to players for a 'real' performance.
So where things are now is that we have all these one note special purpose libs and patches for glissandos, brass rips, tremolos, etc.which have no 'MIDI' or notation value at all... they're just triggered FX. Because there's no way with standard MIDI to do them.
Now Steinberg has a good part of the solution: VST Expression. But who really supports it? No one. So things are stuck.
It would be a -fraction- of the effort for VSL to incorporate Steinberg's tech into their lib as it would be to create a notation program. Maybe that would kick other vendors Sibelius/Finale? into supporting it as well. I wonder how Logic would feel about it.
It would also require VSL to create an UBER MATRIX for each instrument that incorporates -all- the gestures a real player uses in a typical performance so that one could put a complete performance on a single MIDI track... and thus a single notation staff. If you think Dimension Strings is RAM hungry, I can only imagine how much RAM even a few such instruments would require. Perhaps the answer likes in virtual instruments
Iifn short, one must currently choose between 'realism' and notation. There is no middle ground. And the user-base (and the marketplace) have spoken... they care less and less about music based on traditional skills so I seriously doubt whether such a 'dream' will ever be realised.
Within a few years, I doubt there will be more than a few commercial 'composers' who even read music well enough to prepare a traditional score. Sample-based DAW productions will be the normal end product and when/if 'real' players are required, one will simply hire a new breed of 'MIDI Copyists' to create an approximation in notation.And slowly, the whole concept of 'orchestration' will die because no one will give a 2nd thought to what is actually playable... Sort of like that guy Conlon Nancarrow and his Music For Player Pianos.
As a result, these MIDI Copyists will be well paid and people will guard referrals -very- carefully because they will be expected to translate DAW/MIDI renderings that will often contain -many- unplayable passages. And eventually? As samples get even better and the translations to notation become ever more disappointing, the whole idea of translating -anything- generated in a DAW to notation will be dropped.
---JC