The only thing All-Madden does is bump up the computer sliders and lower the user's. That includes "Pass Reaction" and "Run Reaction" sliders. As a rsult, on a scale of 100, the computer goes from 50 to 75. The user goes from 50 to 25. That doesn't change how bad the computer is at finding running lanes or making reads. If you use custom sliders, it is no longer All-Madden, it is custom.
I just get the impression that the game is built for heads up play, and not against the computer.
I AM glad that they have tendencies this year. It helps make players like Vick actually tuck and run. While not perfectly tuned, it does improve the game play.