"but in terms of what both teams accomplished on the field, they stand fairly equal."
Good to hear you now agree that NC >>>>>>>> Non-BCS NC.
Regarding individual accomplishments of BYU 1984 vs. Utah 2008 or whatever, I'm sure that's been debated at length on this board, and frankly, this thread is getting long enough.
What I can say is that I'm sure there are plenty of better teams in history that would likely beat BYU 1984 and Utah 2008.
But the fact is, BYU was recognized as the best team in 1984. Not just because they went undefeated, or beat certain teams, but because they were the best team. That year, no other team can claim being the best. BYU can. Hence, no.1 and hence, the crystal Coaches' Trophy garnishing the halls at BYU.
In 2004 & 2008, some other teams can claim that honor. Utah can't (though some fans try). Yes, they went undefeated. But they did not dominate. There were other teams left who were recognized to be better.