5. Speed and confusion on defense: I view this like volleyball. In volleyball, players start where they have to be by rule and then move to where they want to be to make the best play. Defense in football should function that way, where players lineup in the same position every down so as not to tip the play and then proceed any where on the field to make the play that is called. The best way to do this is to put as many fast, "versatile" players on the field as possible.
I favor a 1-5-5, 2-5-4 or even any 0-X-Y defense with linebackers spread across the field, four or five safety/corner hybrids on the next level and very few down linemen. At the snap, any of the non-linemen could blitz, position for a run, spy the quarterback, stay in a zone, drop-back into coverage or pinch receivers. It's kind of like the spread offense on defense - whether the spread has made its way to the NFL or not.
In conventional football, it is a strategy to make the purpose of a down lineman to be blocked in attempt to free other players to make the play. Limiting the number of down linemen removes the advantage that the offense has of knowing what players are going to do and who can be easily neutralized. One or two linemen in the middle could be beneficial for discouraging plays in that direction where this defense could be otherwise exploitable.
The current "prototype" linebacker has the speed, strength and athleticism to be equally adept at rushing the quarterback from any spot on the field, spying the running backs or playing in (mostly zone) coverage. Athletes of today allow for the defenses to have the advantage in confusing the offenses – not the other way around.
Paul Bessire is the Senior Quantitative Analyst and Content Manager for WhatIfSports.com and a member of the Pro Football Writers of America. With any comments, questions or topic suggestions, Paul can be reached at firstname.lastname@example.org. Thanks!