The playbook was massive, assignments were unclear and there were so many different protections that linemen were overloaded with responsibilities.
It resulted in the Bears finishing the 2004 season with the worst offense in the NFL.
New offensive coordinator Ron Turner will not make the same mistakes.
According to quarterback Rex Grossman, "The most common phrase I hear is, 'We're going to do what we do, and we're going to get good at something before we move on.' Last year the volume of our offense was huge.
"We're (not) going to move on to another play or move on to another package (until) after we get really good at something first. I think that's a comfortable approach for everyone."
Turner has been preaching that concept almost since the day he signed on for a second tour of duty as the Bears' offensive coordinator on Jan. 9.
"The key to our success is going to be execution," said Turner, who was also the Bears' offensive coordinator from 1993-96. "We're going to have enough (plays). We're going to have plenty to attack anything we see and be able to do what we want to do. But the key is going to be these guys believing in it, which I think they do, and to come out and execute."
Ask Bears offensive players off the record about the execution of last year's offense, and most would admit they were in favor of it.
Wide receivers coach Darryl Drake was around last year and sees the dissimilarities in the installation of the two offenses.
"Because that playbook's not as thick as it was last year, it gives (players) an opportunity to home in on some things and to get better at certain things and not have so much volume that you really never get good at anything," Drake said. "That's one of the keys to performing consistently and being able to perform with confidence. Guys are able to do those things over and over. It might be out of a different formation, but you understand, you know that play, instead of having an offense where you run 65 plays and you never repeat any. That's one thing about this offense; you get good at stuff."
Wide receiver Bobby Wade said players have the opportunity to master a smaller portion of the offense before moving on to the next group of plays.
"That's the idea, instead of just throwing things in and not grasping it," he said. "We come out here and drill something until it's done right. Coach Turner said he's not going to call a play in a game that doesn't work in practice. He told us straight up, 'If it doesn't work, it won't be called.' That's all you can ask for. Last year, we just had a lot (of plays) going into the game, (but) we didn't necessarily have it all down."
That won't be an excuse this year.
"You're not going to come out and hear a play that you didn't know in practice," Wade said. "We want to get it exactly right. If we're losing games, it's not because of not knowing the offense, it's not because we're not studying the playbook, it's because the players aren't making plays."