In 1984 the argument against BYU was that they hadn’t beat any good teams, reference Barry Switzer’s reference to “Bo-Diddley Tech”.
All we know about Indiana is that they have beat everyone they have played. It doesn’t mean they are a bad team because they haven’t played any great teams. It means that we may not really know good they are.
They might be the best team in the country. I guess we will find out in the next few months. Assuming you believe the best team always wins.
BTW, I do believe that BYU was the best team in 1984. They had a few very good years leading up to 1984 and that 1984 team was stacked with talent.
I looked into it several years ago, and if I remember correctly, 13 players off that team were drafted into the NFL. Not all in the 1985 draft, but including following draft years, 13,players that were on the 1984 roster were drafted.