Two of the greatest sportsmen in the history of sport who have won great acclaim and are considered the best (one unarguably, the other definitely the greatest modern player) in their respective sports, but haven't still been able to shake off or disprove criticism. That Sir Donald Bradman was considered very susceptible and not so highly rated on wet pitches was a revelation from the Picador Book of Cricket anthology that I'm reading now. Pete Sampras's inability to win the French Open is a well-documented gap in his resumé. Both were undoubtedly one of the greatest men to play their respective sports.
So while measuring greatness, one has also got to take into account what heights they scaled in what would be considered their strongholds and to what extent they progressed against the odds in the ones they didn't fancy.