I think Ace makes a fair point. We should agree to disagree, since at the end of the day, we're only speculating and presenting our own opinions.
For example, Ace said: "...I wouldn't question a valid retrospective opinion of [Sampras]"
BP said: "I would because Sampras is clearly wrong"
To me, both statements are much stronger than what we can substantiate with evidence. Is Sampras' retrospective opinion unquestionably
valid? No, as BP argued. But then, does that mean Sampras is clearly wrong? Again, no. The answer is: we don't know, so we cannot rule anything out in such a confident manner.
I wish we could somehow turn the time back and conduct an experiment: let Sampras play with a larger head, and see how many slams he wins. Since we cannot do that, we'll never know the answer... and I guess we'll continue to have entertaining, heated, and opinionated debates on this forum