Bristol_Jonesey
Or simply invest in a reverb plugin that lets you control the Early Reflections and Tail independently of each other.

That's what I meant, do none of Sonar's standard offerings allow this?! 
 
And yes, Williamcopper, PC is an alternative path, although technically it's in series with the FX bin and you can put the whole thing before or after the bin. You can also put an FX chain (which is kinda like a regular bin) inside a PC chain if you need some modules before or after your VSTs specifically. I think both PC and bin are pre-send though. It would be nice if we could insert a send like a VST wherever we want in the chain. 

williamcopper
 
Here's another troubling feature about that image:   it appears that the ProChannel is an ALTERNATIVE path to the FX bin?    That might explain why I always feel that using anything on the prochannel messes up the sound....

That path is misleading for PC and really should be redrawn. What it means is the PC can be set pre/post, not that it is a parallel path.

Bristol_Jonesey
Or simply invest in a reverb plugin that lets you control the Early Reflections and Tail independently of each other.

Sure you can do this manually, and you could go even a step further and play with delays, pan, phase, eq, etc, and accomplish your own positioning.
 
I expect that VSS attempts to do all this for you.  I like the idea.
 

Sanderxpander
It would be really strange if you take care to carefully position each instrument and then destroy that imaging by putting them all through a reverb as if they're in the same spot.

I imagine you'll only destroy the imaging if you have too much overall reverb.  The instrument itself (going through VSS) should not go on to a reverb.  I see VSS as just providing more control on what happens within the space.  Things will have to be balanced to achieve the right effect.