It's been known as the "Sears Tower" as long as I can remember. It's probably the next most famous building to go to the top of, other than the Empire State Building. I've seen it referred to in countless news stories and seen it described in documentaries. I don't see why new ownership should change the name of a famous landmark. That is ego and vanity in the extreme on the part of the buyers. Of course, it isn't going to end the world that they've changed the name, but it was unnecessary,
selfish and silly for Willis to do so. In the end it's like Gary Busey says "There's nothing like changes, cause nothing changes but the changes".
"One of the many, the proud, the friends of Zardoz".