Pete Sampras can't win.
He's damned if he does, damned if he doesn't.
Some say he only won salms because of his serve. Some like the OP suggest his serve isn't what it's made out to be.
So which one is it?
I'm willing to bet that if you asked one million knowledgeable tennis fans which one player they would choose to serve for their life, the majority would say Sampras.
Stats only tell half the story.
That is all.