I agree that it may very well appear that running backs are too powerful in this game for the user and if tweaked too high also for the cpu. However, If you take into account (as I have stated) the schematics of a defense and an offense relative to the individual assignments of each position it will then be understood that by attempting (in this game) to "tone down" the abilities of the players, such as a running back, you will also have to tone down the defense's abilities which will in return create a snowball effect while playing in which nothing will quite feel right because it is not what you see in the NFL.
Running backs can be "shifty" a lot of times and hard to stop, but containing them using your linebackers and safties is how you counter that. If you were to take that part of the game away from this video game, then ultimately you are cheating yourself out of the realism that is the dynamics in football in general. If in a game running backs aren't juking as much and aren't as elusive then you have a dull game that may produce real stats but at the "cost" of the dynamic plays. Most people (I have observed) who post threads for sliders have this theory that you can not have both realistic gameplay and stats because users will "cheese" the game and outsmart their opponent's defense (especially the cpu).
The fundamental issue here is that in Madden (this one especially) the defense has weapons of its own but of course one must understand the "schematics", as I always talk about, that is defense in football to know how to utilize these weapons. Honestly most people who watch and enjoy football pay attention to the offense because it is what part of the game that appears to be most active and exciting. They miss completely that there is a "whole other world" so to speak on the other side of the ball. So when these same people post these setting they are doing it from an offensive perspective focusing on how to make the offense either more or less dynamic missing completely that it is about balance, therefore they should really be focusing on how to counter the offense with what the game of football has intended to be the counter...DEFENSE!! Yes I love defense just as much as offense, but more than that I try my absolute best to remain objective through all things in life because ultimately life is about that. Sorry for the brief philosophical rant. lol