I'll put in my homer statements, why not... Carolina Panthers
Mike Tolbert bolsters the 3rd ranked rushing offense in the NFL
Ron Edwards back from injury adds a veteran presence to a young DT group
Jon Beason and Thomas Davis both coming back from injury
Luke Kuechly is ready to start and be a difference maker immediately
Joe Adams is a starter for punt and kickoff returns, goodbye Armanti Edwards (30th in NFL in punt returns)
Jason Baker was 28th in the league in punt average, Brad Nortman/Nick Harris should be an upgrade
The Panthers kickoff coverage team was 25th in the league, they allowed 3 punt return TD's (last in the league), they allowed 13.3 yards per punt return (30th in the NFL)... they addressed that with special teams players like Kenny Onatolu, Haruki Nakamura, Reggie smith, and Mike Tolbert.
Sherrod Martin was one of the worst safeties in the league last season, he should lose his job with Nakamura, Smith, and rook D.J. Campbell all fighting for the job
David Gettis is healthy for this season, after missing last season. Had a decent rookie year and is a huge upgrade over Legadu Nannee. Gettis had 37 receptions for 508 yds and 3 TD's in a 2-14 season that had Brian St. Pierre and Jimmy Clausen throwing the ball.
Mike Pollack and Bruce Campbell add depth on the o-line, and the jury is still out on Campbell.
Amini Silatolu will start from day one at LG and is an immediate upgrade over Travelle Wharton.
The Panthers really didn't lose any difference makers (Maybe Dan Connor who came in for an injured Beason, but Kuechly is an upgrade).
They return the 5th ranked scoring offense, 7th in offensive yards, 13th in passing and 3rd in rushing. They plugged major holes on a special teams unit that was almost dead last in every major statistic, and they return three starters on defense (5 if you count 2nd year players Mclain and Fua) to help a team that finished the season 4-2.
I don't think they are most improved, but for sure one of the top 5 improved teams and one nobody is talking about.