I've yet to hear any fan-on here at least-tell anyone how great IU is. Like I said, I get the skepticism. Heck I'm one of the most irrationally optimistic and naive people around and I'm skeptical that this will continue.
But take away IU's previous three years, and IU would absolutely be ranked in the top 5 without anyone raising an eyebrow.
With that said, I'm not sure I understand that your prediction is that much different than most on this board. I believe that IU will lose a few games which it is favored. Though the schedule opens up a little bit after the visit to Columbus, I can see IU losing back to back games or 3 out of 4. And if IU is out of the tournament by the end of the first weekend, I'll be disappointed but not terribly surprised.
Most IU fans are more excited because this year's team wasn't supposed to make the NCAA tournament, although I predicted it would. So the fans' excitement isn't that this year's team is going to be great necessarily, but rather if this year's team has overacheived, think of what happens when they replace Daniel Moore, Tom Pritchard, and Verdell Jones III with the top level recruiting class that is coming in.
Even if IU went .500 for the rest of the regular season and finished 10-8 in the B1G Ten, they'd have 1 more win than the last two years combined. If they continue on the path that I'd expect, they'd be in position to win 28 games (including the B1G Ten and NCAA tournaments) which would tie the last three seasons. So it's not how great are we. It's how lousy were we and how much better is it to be a top team.
Of course it doesn't actually work that way, but that never gets in the way of fans' assumptions.