No, that would not be the situation necessarily.  Divisi Strings could be an addendum.   It is actually quite similar to the brass.  If you have Dimension Brass, you have the auto divisi, the blending of 2, 3, 4 players with no worrying about phasing, the new solo player sounds, etc.  However,  you still like using the solo Cornet or the original Ensemble Trombones, or the Epic Horns, or the Piccolo Trumpet, or the Wagner Tubas, or the Cimbasso, or in fact, all the older VSL brass libraries because they are perfect for certain situations. 

I for example would sooner give up a limb rather than Epic Horns.