Having been a trained classical bassist, I continue to be - at least somewhat - amazed by various requests, and the dominance of a "Hollywood sound" in those requests (granted scoring for film is one of the major means of potentially earning money).
Looking at LASS, among others, while it does section divisi well, its limited articulations in no way reflects what a real player can do with a bow. One may gain realistic divisi, but end up losing a far greater degree of realism with the severely limited articulations.
IMO, it is of far greater importance to learn to write string parts that are nuanced in ways players would play them, than to have "perfect" divisi. For traditional two part divisi, the resources already exist within VSL to do that fairly well: layer orchestral and chamber strings for the orchestral string sections, and when divisi is needed, play one note using orchestral strings, and the other using chamber strings - not perfect, but still a good alternative.
I really agree with Beat.
To my ear, VSL's strings come the closest to the sound of a real orchestral string section. Are they perfect? No. But comparing them to various competitors, VSL comes far closer. Note: one of the things I would wish for would be articulations where the bow is left on the string after the note is played. A real player will often leave the bow on the string during very brief rests, as taking the bow off the string for a short period of time, and them putting it right back on the string is wasted motion. As long as the bow does not move, no sound will result.
Now would Dimension Strings be a good thing? Most likely, yes - provided it contains a full range of articulations, and/or does not introduce other major compromises.