Piniella won a WS in the 80's. Had some pretty stellar players in Johnson, Martinez, Griffey, A-Rod, Ichiro and a host of other complimentary players like Boone, Cameron, and Buhner.
He did nothing with the Rays when he was there, and then inherited a pretty stout team with the Cubs and won what? Two early exits in the playoffs and not one single win?
And Leyland? Not taking anything away from either one of them as a manager, but to imply that Leyland had Barry Bonds, Bonilla, and that team with the Pirates, the team the Marlins assembled in 97' with Sheffield, Bonilla, Johnson, Leiter, Brown, Alou, Renteria, and Nen, and then the teams that Detroit had after the rebuild was already in place when he joined them in 2006 with Granderson, Verlander, Rogers, Ordonez, Guillen, Young, Pudge, and an "at the time", lights out bullpen with Miller, Grilli, Rodney and Zumaya.
Not exactly walking in and opening up a bare cupboard.