I think what hurts Columbia are its odd application system, rep for yield control, and the fact that its a finance school so in the M7 is competing against GSB and Wharton both of which seem to have a big advantage recently. Much like I think in a way GSB not publishing its admit rate hurts a lot of people's opinion of its selectivity...since they dont give a number people assume it must be a lot easier to get into than the other M7s that publish data.
I believe Columbia is redoing its curriculum which could help its standings. I think its just the general feel that Columbia has been falling further behind the other M7s. Schools do move, I know someone who went to Chicago in the 80s and was blown away by my getting into Kellogg but not Chicago since back when he was there, Kellogg was considered a far better program but now they are on par. So for schools to move up someone has to move down.
I definitely agree that there is the super ultra mega elite of H/S and then the ultra super elite of Wharton. It is extremely rare for anyone to choose anther school over H/S, even Wharton...thats why I see it more of the big 2 and then wharton, because most people who get into Wharton but not H/S end up there.
I would say Ross has a leg up on Duke, especially once its new facilities are done. Its not a knock on duke which is a great school but Ross just has an advantage in some programs and reputation in a few of the bigger areas like GM...yes Duke has some top notch programs but they are slightly more niche areas.
NYU I would say is an elite, its second fiddle to Columbia in NYC. There is a difference, its possible it could move up to be a par school (see GSB vs Kellogg) but at this time I think it still trails Columbia. Location NYU definitely has a great advantage over any other finance school, heck its even got an advantage over Columbia since its almost on Wall St.
Now the disclaimer. I only applied to GSB/MIT/Kellogg...I had negative interest in HBS, no interest in Wharton, and no chance at Stanford. I dont want finance and the cost of living is too high in NYC so no Columbia. I was planning on applying to Duke and Ross in R2. Dropped Tuck because of location and poor job market for Mrs. Riverripper. Not a west coast guy, would rather a blizzard than an earthquake so no Haas. This is my opinion from interacting with other applicants, current students, and alums...no scientific study was done to verify the information contained above. We can revisit this subject in 5 years and see how horribly wrong I was or amazingly predictive this post was. See you then.