Well, fumble or not, the coaches will tell you that it should never come down to one play like that.
Sure, if they had reviewed it and overturned it, it could have led to a Warner/Fitzgerald Hail Mary Miracle. But then people would be crying that the Steelers were robbed.
If the Steelers hadn't held in the end zone...different outcome. If the Cards hadn't committed so many personal fouls...different outcome. If Warner hadn't thrown the INT that led to the 100 yd TD return... different outcome.
In the end, both teams actually deserved to win, but only one team can win.
I'm just glad that there have been a couple of good Super Bowls to watch the last couple of years. It had gotten so pathetic for awhile that it was almost embarrasing to call anything associated with the game "super".