What we knew then...
Winn was about to be 29, about to get expensive, and over the last three years hit .283/.353/.418 while playing pretty solid defense. You could argue he was the Rays best or second best player right alongside Aubrey Huff. Naturally, the Rays traded him.
For a manager. *
This deal was ridiculous from the get go. Anyone who thought Piniella and Piniella alone would make a difference is severely overestimating managerial affects on performance.
What we know now...
Lou Piniella, local legend and probable savior. Here he was, home to rejuvenate a lowly franchise through the only means he knew how: kicking and screaming. Piniella was promised payroll raises by management ... and you know how the story ends. Piniella should be thankful LaMar and company didn't spend more money on the guys they wanted to. Although, Carl Everett running around the clubhouse while screaming about how those mother-effin' pterodactyls would fly before Piniella could talk to him like that would've been entertaining.
Winn went on and kept playing well, FanGraphs WAR has him at 4.5 wins his last season with the Rays, and 25 WAR total from 2002 until present day. Perpetually underrated, it's not a stretch to think Winn was a top five player in this franchise's history, and still is if you refuse to include active Rays.
I don't have much else to say, this move was never going to end well unless Piniella brought Mike Cameron, Carlos Guillen, and Freddy Garcia with him.
*To be fair, they also received Antonio Perez, a mildly interesting prospect who was later traded for Jason Romano. A "second baseman" that hadn't actually played second base in a while, and would later be released when they found out he couldn't play it at all. Yep, those are the D-Rays