The explanation is ludicrous, IMO:
"It's a one-year break, said Jaime Weston, the league's vice president of brand and creative, because the "L" isn't as pleasing to the eye.
"When we developed the Super Bowl XL logo, that was the first time we looked at the letter L," Weston said. "Up until that point, we had only worked with X's, V's and I's. And, at that moment, that's when we started to wonder: What will happen when we get to 50?"
X's, V's and I's are more pleasing that L's??? WTF?