Based on what? From what I saw last season, Matthieu is a much bigger weapon when he's closer to the line of scrimmage. The more you as him to play on the back if his heels, I think you're playing away from his strengths.
Based on his ability to diagnose plays and react. He had several big plays playing from the FS position. Playing FS is not an on-the-heels position, it's a playmaker position where you have the luxury of diagnosing and breaking on plays. Yes, Mathieu is great in the nickel, and excels when brought up in the box as well, but FS gives the best field view and luxury of moving around based on personnel on the field. He's one of the quickest guys to diagnose plays I've seen and in slowmo you can see him moving in the right direction before other players even twitch. At the FS position, he may have a bit more ground to cover but he also has a better vantage point. He played a lot of both last year.
IF you have another fast, highly athletic CB who can make plays, you want to have that guy on the field WITH Mathieu rather than sitting at CB4 and coming in for dime packages. Peterson, Cromartie, Mathieu, Bethel are all very, very athletic and all have high football IQ. Add Deone at SS with a knack for hitting, and that's a wildly entertaining secondary.
Which is why I'm most interested in seeing if Bethel is doing as well as it's been said, and why I do feel he's a potential difference maker...not because he himself will be off the charts, but due to HB's versatility we could boast the best overall secondary in the league (which would come in handy when not having a strong pass rush).
