I can't provide anymore information as to whether sliders help or not. I played the game briefly on both PS2 and XBOX and in both of them I tried a few sets sliders on both All American and Heisman. I can't remember the exact sliders, nor can I pretend to have extensively tested potential solutions.
Maybe you are having better results with whatever settings you're using and the issue is manageable on your end. You've obviously played this game more than I have. For me, the issue was immediately noticeable and the few sets of sliders I've tried didn't really help it all that much. This coupled with the fact that I've seen reports of the issue not being fixable (which could have been wrong I guess) and reports that tons of school end up on probation in dynasty mode made me move away from NCAA 08 fairly quickly last year.