Sim stats are terrible

Sim stats are not very realistic. Far too few pass attempts. Completion percentage is too high. Not enough interceptions. Too many sacks. 

Running backs don’t break off enough long runs. Non superstar running backs struggle to be above 3.5 yards per attempt which is horrible. 

Can we get more transparency on how this sim engine works, and if there’s any way to fix it without rebuilding the sim engine from the ground up?