For what it's worth, I have spent so many years trying to get VSL Solo Strings to sound as good as a real player that it has become obvious to me it's an impossible thing to create. Unless the part is so basic and so minimal, and then also only spands a few measures I can pull it off. But if I expect to pull off more than that, I have revert to hiring a real solo player. I tried for 3 months to get a simple performance to sound strikingly realistic but in one day, I accomplished this with a real player and a small amount of cash.
I do find the solo strings great for fast, shorter note stuff though such as classical Bach and other musical literature that doesn't require extremely expressive long notes, or dynamic moments. They are amazing to layer with as well. They have a beautiful raw sound to them.
I know that great things can be done with the solo strings but even being the best ones you can buy on the planet, they have limitations and as Daryl said, I can't even imagine what it would take to recreate that type of performance. Perhaps a Sample Modeling type string instrument but the problem is, it's far more difficult to create a sample modeled string instrument than say a brass or wind styled instrument. It would take much skill to operate a sampled instrument of a Violin and create a perfect performance that contains every aspect of a top notch world class player (which is what our expectations are/would be). Also, how much time do you have to edit and edit and tweak? If you have unlimited time, and devote yourself to perfecting it, even more possibility opens up to you but it's often hard to remember the vast amount of possibilities that are already available, let alone add a gazillion more options that I will forget are there.
I am happy with them for what they are, but they simply cannot replace a real player (and honestly, I am glad for this to save all of our musician friends).
Maestro2be