The defensive backfield is the most improved position group on the entire team, and the back end is the most vital upgrade with the most profound ripple effect. Having a legit cover guy at FS (primarily Randall but also BBC) allow Peppers to play closer to the line where he closed very strong last year.
Ward, Carrie, Gaines, BBC, Randall, Peppers has me very, very stoked. About as massive of an upgrade as you can make to a position group. I expect 5 of those guys to be on the field a ton, sometimes all 6 when Peppers is basically one of the two LBs.
Agree, EE, has to show up on the field... but for now, it's the most astounding influx of talent I can recall seeing from an NFL team in a single offseason (trades, FA, draft). You can look just about anywhere (today, RB seems appropriate) and go, "Holy shit. We extended Duke, signed Carlos Hyde, AND drafted Nick Chubb? All those things?!"