I think the unification of UI is not so much a matter of comparing
Inskcape with Gimp and Scribus but rather Inkscape with the rest of
GTK (and even QT) apps out there. Most of them are or will soon be
using Tango icons, at least because of the mere fact that Gnome uses
them so all stock icons will be Tangoified. So it is about having a
entirely unified desktop rather than just a suite (and this would
definitely matter to me... if I was using Linux ;))