I suppose that you could point out something out of the ordinary in every season. This is an interesting exercise!
The 1969 season was a little different. The Jets won the Super Bowl at the end of the 1968 season in January of 1969 and you wondered what was going to happen next.
The Packers were no longer a factor. In fact, Vince Lombardi coached the Redskins that year. John Unitas was healthy again but the Colts did not reach the playoffs. The NFL champion Vikings were a bit out of the ordinary because their QB, Joe Kapp, had a different style of play. The Vikings had that stellar defense and played home games in a frozen stadium where both teams stood on the same sideline. It marked the fifth straight year the NFL's Western Division champs won the league title.
The entire AFL season was an afterglow from Super Bowl III. But the Jets did not return to the championship game. In fact, in retrospect, Joe Namath played his final post season game that year, losing to KC. Then the Chiefs matriculated the Vikes into a disaster and won Super Bowl IV easily.
If you don't classify the 1969 season as odd, then I guess you have to say there were some significant changes which got their start that year.