But does she need to do the same "standard" songs at every show, or are we far enough removed from them that she can get away with it? Specifically, "Hero", "We Belong Together", "My All" and "Heartbreaker" are getting annoying. I know WBT should stay, but the others don't need to be performed at EVERY concert. Yes, even "Hero". I think people would notice but I don't think that matters. Stevie Nicks doesn't perform "Landslide" at every show anymore. I noticed when I saw her live, but I was also grateful to hear some rare stuff instead.
I wouldn't compare Mariah to Madonna, but Madonna's setlists are so varied from one tour to the next, and both have enough of a back catalog and enough hits that Mariah could do the same. Or like Janet who is probably the best at putting medleys together so you get more songs represented within a short period of time.
Mariah needs to let go of the assumption that people will go home and cry if she doesn't sing "Hero" or "Always Be My Baby". Sure some people would say "I can't believe she didn't do ____" but who really cares? I think changing things up constantly would draw more of a crowd anyway. I know that I really haven't gone out of my way to see her live in recent years because it's kind of like a "been there done that" kind of mentality. Except for the Beacon show I went to last year, which I was excited about because I hadn't seen most of those songs live before.