I think AH has been living off it's rep for far too long. Lots of blue hairs and faculty that will ask you to sit down and not enough students close to the floor. Couple that with the fact that it has some of the worst sight lines and views for a pretty large percentage of the seats. It sure looks cool on TV with that severe steep pitch, but it's not a great place to watch a game for many/most attending.
i haven't lived in IN for 30+ years so haven't been to a game in Mackey in that time, but I think they've steadily improved the aesthetics and it looks like a pretty good environment. Also, doesn't hurt that they've had better teams and I think if they'd had the on court product IU fans have had to put up with for much of the last 25 years, they'd have far fewer butts in the seats, no doubt.