Tre, this is also an excellent point.
With all the focus on the infinity engine quirks, it kind of hides some of the other concerns. I also agree that playing with each of the 4 teams didnt really yield a different experience and set of tactics and strategies. I really never got a true sensation of the differences in styles of play or player abilities. When I load up a game of ALL PRO 2K8 with the NFL Rosters, I can clearly get a feel for the different players strengths and weaknesses which make for a much more diversified gameplay experience with each of the teams.