First, you can't just use a solo violin multiple times. This results in a "phased" sound. That's complicated so I'll stay away from explaining that. But another problem is the fact that you have the same performer and the same violin playing everything. Although ideally it may sound like it would work, it doesn't. If you loaded 34 of the same violin to try and build a section you would get a sound that isn't very realistic.
If you have a full string section, but record it in a way that you can use an individual portion for divisi, then you can both have divisi and also use them all together for the lush sound of a full string section. This doesn't just provide realism in sound and in divisi-bility but also realism in being able to adjust the timing of each section to be slightly 'off'. The key to emulating human performance is imperfection. By adjusting muliple sections, or each instrument individually to start at slightly different times, one can control the 'loose' or 'tightness' of the performance. Composers may intentionally want an extremely loose performance. DVZ has developed a system that accomplishes these things very well. I would like to see something equal or superior from VSL and recorded with VSL quality in recording methods and performance.
But at very least, VSL users definitely want divisi and a Violin II. Doubling Violin I samples as a Violin II section comes with the same problems I mentioned before.
-Sean