The game does play a little different on slow speed vs normal. It is not as bad as M15's slow speed but it does seem a little easier when on slow for some reason.
Having said that you can get beat, it just depends on how the opponent plays on the day. I have tried All Madden using Joshs setting and a slow speed and I would agree with you. It is total b.s. All pro is the way to go and try using normal speed and see what you think would be my advice.