Did a scan on Pro Football Reference for 10 win season with a total turnover of their passing, rushing, and receiving leaders for the next year, and then threw out the ones where it was an injury the next season, or another dude just happened to lead in receiving yards or something. (Tossed out old examples from when the passing leader would be a halfback with 200 yards or something, too.)

This appears to be the closest example:

2001 Ravens: Went 10-6 and won a wild card game. Elvis Grbac was cut and retired, Terry Allen's contract expired, wasn't renewed and he retired, and Quadry Ismail went to the Colts. Allen was a fill-in option because Jamal Lewis missed the whole season with injury, so the Ravens weren't moving on from the guy they had intended to be their #1 running back in 2001. They went 7-9 in 2002.

Other interesting examples:

1972 Cowboys: Coming off a Super Bowl win and 11-3 regular season, the Cowboys benched Roger Staubach in favor of Craig Morton, traded RB Duane Thomas, and benched Bob Hayes. Staubach and Hayes remained on the team, however. They went 10-4 and lost in the divisional round.

1972 Colts: Coming off a 10-4 season and a loss in the AFC championship, they jettisoned Earl Morrall, and benched Johnny Unitas. Norm Bulaich and Eddie Hinton had significantly reduced roles in 1972. They went 5-9.

1972 Vikings: Coming off an 11-3 season and loss in the divisional round, the Vikings got rid of QB Gary Cuozzo in favor of re-acquiring Fran Tarkenton from the Giants. RB Clint Jones lost his starting job, and WR Bob Grim was part of the trade for Tarkenton. They went 7-7.

1984 Steelers: They'd gone 10-6 in '83, with Cliff Stoudt replacing Terry Bradshaw after his career ending injury, and with John Stallworth missing most of the year. In '84 Stallworth returned and '83 leader Calvin Sweeney was benched. Stoudt went to the USFL, and Franco Harris was cut. They went 9-7 and lost in the AFC championship game.