Sure he did play a big part in the club's revival. And then he tarnished his legacy by failing in Europe and using pathetic excuses that made a mockery of the Juventus brand, said the club wasn't capable of competing in Europe, and abandoned the club on the back of this failure at the worst possible time. And has continued to take pot shots at the club and its management since.
His legacy/legend isn't at all bigger from his coaching career, because he tossed it all away by acting like total bitch at the end.