I use the newest Average Joe Varsity sliders "as is" except I use revamped passing on 40.
My season completion rate is usually a bit over 60%. It works well for me.
We're all different and I'm sure many could jump into my game and want to turn down my 40 because it is too easy for them, and that's why Armor's sliders are a starting point. I don't believer there is a wrong setting, ie a setting that gives a user realistic numbers is a good setting.