My view is that you need everything... the only issue with the VI Series strings compared to the libraries recorded with 10+ mic positions is the tonal realism.
I feel like the ultimate combination (if they decide to do it) would be the Synchronized Dimension Strings combined with Synchron Strings I, and then maybe a Synchron Strings II with some additional articulations (detache, a super slow/soft legato, harmonics, col lengo, portamento).
With VI Orchestral Strings alone, compared to SyStrings, you just don't get quite as much depth of tone/sound. PLUS with multiple mic positions, you can treat the sound with different FX (some saturation, pulling a little more harmonic content, etc). Great for a mixer!