I seem to remember improvement in games for the PS2.
2002 was better than 2001. They were able to add Coaches Club and re-alignment of the conference divisions, allowing you to create an expansion team. Also adding unique faces to some players and more player animations than was in 2001, the first game for the PS2.
2003 was better than 2002 giving you more to do in franchise mode by getting scouting reports of players and integrating player progression logic. Not to mention gave you the ability to create-a-playbook.
2004 was better than 2003 as it added the ability to change player routes and assignments, directing the blocking as you run with the ball (Vick in this game running out of the pocket), and they introduced the Owner mode allowing you to operate more than just your rosters.
2005 over 2004, introducing the hit stick and creating more pre-snap options for the defense. Also gave us new features in franchise mode such as Tony Bruno radio and the newspaper with storyline central. They also had player personalities which players actually acted like T.O. or holding out like Revis.
2006 over 2005 they added the vision cone to give players a way to distinguish skillsets of different quarterbacks, not to mention the ability to throw to a spot on the field or lead a receiver or throw it high or low, in other words total pass control. They added the truck stick to help players break tackles. Also introducing Superstar mode.
2007 over 2006 they gave you the ability to take control of your fullback and actually try to leadblock. They improved on Superstar mode. They introduced more to the franchise mode such as college allstar game and gave more scouting reports. Not to mention new player roles which gave players abilities.
2008 wasn't much of an improvement over 2007, but they refined some features and created better AI to allow players to make the use of their abilities, in otherwords, on field smarts. They added a new feature in franchise mode allowing you to scout opponents by getting reports of their plays and their star players to watch out for.
So basically, in a nutshell, when they had a reason to make a good game, they did. In a year's time.