Getting VSL to work with Dorico is not the problem. What works with halion works with VSL (and Spirfire, and Orchestral Tools and you name it) one just has to adapt the expression maps, which, for some strange reason, seems to be rocket science for most people. Accomodating the Hollywood orchestra would be a real challenge though…
The problem, especially for third parties is that Dorico’s Expression map system is work in progress and also not documented.