Roethlisberger was 22 years old when he played in SB XL. You can't compare his performance in that game to his peers because 99.9% of QBs are never in his position at that young age. What were Rivers, Eli, Aaron Rodgers, Palmer, Romo, etc... doing when they were 22 years old? How good were they? What level were they playing at? They were either too young or not good enough to be in Big Ben's position or anything close to it.
And despite XL, he still finished that playoff run with a QB rating over 100. Three straight playoff wins on the road for a 22 year old QB (a first in NFL history), including outplaying Peyton Manning in Indianapolis against a team many were considering as one of the best of the decade at that point (won their first 13 games), and demolishing a Broncos team in Denver (where they hadn't lost all season and had just defeated the Patriots), completing over 70% of his passes, throwing 275 yards (at 9.5 YPA) and totaling 3 TDs. How many other 22 year old QBs have played like that in the AFC Championship game on the road? Oh, how about none.
As far as XLIII goes, did you watch the game? Roethlisberger was pretty much tremendous when he had to be, his only real error coming on a ball that was tipped by a defensive linemen at the LOS that was intercepted. And it's hard to blame a QB for an INT that is batted into the air at the LOS... it's not like it was a dumb decision, more bad luck if anything. The Steelers didn't pass a lot in the second half when they were up 17-7 and then 20-7 entering the fourth, but that's no knock on Ben. When he was backed up against his own end zone after a great Cardinals punt with the game tightened up, he completed a huge third and long from the one yard line out to the 25 yard line that was ruled back by a holding call in the end zone resulting in a safety, and when he got the ball back again he only orchestrated one of the greatest drives in NFL history, culminating in probably the most beautiful pass and catch for a TD you'll ever see in that spot. Finished the game with a completion percentage of 70%, had 8.5 yards per attempt, and a QB rating over 93. I know, completely mediocre, right?

All with his #1 receiver basically serving as a decoy during the game with a significant knee injury.
Comparatively speaking, I don't think many QBs in NFL history have seen the kind of success and level of play Roethlisberger has been at in terms of performance at the same age. If anything, I think Roethlisberger is sort of underrated because of XL, even though I'm not sure most of the QBs he's compared to would have played better during Ben's playoff run when they were 22. He didn't have the luxury of sitting on the bench for three years like Rodgers, or two years like Rivers, or a year like most others. He was thrust into the spotlight at a very early age, and overall played pretty fantastic. The talking heads are going on about Flacco's road playoff wins in his first few years in the league, when he entered this postseason with a career playoff QB rating right around 40. Whereas a guy like Roethlisberger went on the road not having a guy like Ray Rice going off, but instead had a running game that averaged around 2.5 or lower yards per carry in hostile environments (check out Parker and Bettis' stats during that AFC playoff run, specifically in Indy and in Denver... Ben was the entire offense those games) against great teams and played absolutely lights out. If anything, Roethlisberger still doesn't get enough credit, and I think that's sort of the same point KC Joyner is getting at with his article.