In balanced formations, it would make sense for the safety take the deepest stemming route and the line backer to take the shorter depth. This is very similar to to man coverage against two back formations; the play art shows linebackers or safeties covering specific players but it doesn't play out that way - they cover the receiver that breaks to their side of the field regardless of who it is. It would create a natural pick if they didnt.
I say this in many of my posts, but Madden doesn't replicate real defensive coverage. In Madden, player are given a choice of Man, Zone, or a combination of these two; each of these choices has a strength and a weakness. However, teams don't run man or zone anymore in a given play. They run both at the same time in the same play depending on how the receivers run their routes. It's called pattern match coverage. It gives playcallers the best of both worlds with none of the weaknesses. It really bothers me because Madden continues to misinform fans of football on how the game is played leading to confusion about what is "realistic" and what is not.
The real question is why is the offense equipped with contemporary strategic tools and the defense is still locked in the proverbial "dark ages" of counter measures.