I think changing old, insensitive artifacts is coming too close to revisionism for my taste. Our culture hasn't always been pretty, and things like a cross at an old war memorial serve as a reminder of our inability to create inclusionary representations of those being represented. I would be against a cross being put up now at a war memorial, because we are well aware that Christians are only one part of our culture and ought to know that our country shouldn't stand for divisiveness. Crosses at old war memorials, however, do not bother me.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell