The VST-per-server implementation might not, but
there's no very
compelling reason not to have multiple VSTs in a single server serving
multiple clients. That would be less reliable than a dssi-vst type
service can be, but no less reliable than fst, and it should scale
nearly as well. It's been on my todo list for ages...
i still don't think that scales. the cache might still be warm, since
the server is repeatedly invoked, but its still 2 context switches
per-plugin invocation, and i don't think this is reasonable over the
long haul. the point of a plugin is that "its just a function call
away", and whether its a context switch to the *same* server or N of
them, its still a context switch.