He is a World Cup winner (as a protaganist too) which automatically makes him a true champion no matter what. If not for his WC, I would agree with you, despite his number of Scudetti record.
Call me a selfish fanboy, and mind you Buffon is my 2nd favorite footballer ever, but I am glad Del Piero's record stays in tact.
That being said, I hope he joins a Serie A club and extends his Serie A apps record.