Some of you guys are over thinking it (see pre-season David Johnson thread). Shady simply was not healthy last year and the team had all kinds of things going on and being tried for the first time, all the way down to the QB.
The difference this year is he is simply healthy. He's making those cuts and moves he used to make when he was AWESOME. If you're not a long time Shady follower, you may say "yeah, but some of the runs are ugly and he runs 8 times for 9 yards, etc". I point you to the Barry Sander ENTIRE CAREER gametape. Shady has never been that guy that you watch on every play and thing he's making the greatest decision or runs with authority on every play. But what you'll see is when he's healthy, he's used a lot and he's a steady, consistent compiler in FF. And every once in a while, he's magic and on those days, he's unstoppable.
Stay healthy Shady and you'll reward all your FF owners with a top 5-7 season, maybe more.