I can hear that polytonal Stu Phillips cue just by looking at it.
I guess the reason this missing scene stuck with me all these years is that in a way it's the emotional center of the story. Man from the 20th century is suddenly confronted with images and an outline of what happened to his beloved Chicago and his whole world while he slept for 500 years. He stares at it, not wanting to believe the story, while we try to imagine how we would feel in that situation.
Then we're right with him as he asks Wilma for more information, starts going from denial to other stages of grief, sets out for the ruins to learn the truth in spite of the danger. Even in the final "tag" sequence in his apartment we gain more sympathy for his reluctance to get involved in the business, or the people, of the 25th century for fear of losing everything again. All because we were with him in that room at the beginning.
Shame they took it out. I hope I live to see it if it's ever recovered.