Depends on which Wimbledon we're talking about. Today's grass courts are much slower than they were 20 years ago, with a different grass blend that's treated in such a way as to give a truer bounce (basically, the ball slides less than it used to).
Sampras was essentially unbeatable on that kind of a fast surface and would win there at his peak, probably against anyone who ever lived. The Wimbledon of today, which is routinely referred to by the players as "green clay"? Hard to say. He'd do better than Federer would on the old grass with it's utterly errant bounces. But the slower the surface the worse Sampras fared, as evidenced by the fact that he never made it passed the quarterfinals of the French Open, which is the slowest surface of any of the major tournaments.
The homogenization of tennis is really quite a shame. It's really not unlike football, where the fans' appreciation of the passing game has slowly warped the sport into a video game. With tennis, the move has been to slower courts and heavier tennis balls to facilitate longer and longer rallies, with aggressive plays and players unfortunately pushed to the wayside in favor of boring backboards like Nadal, Murray and Djokovic.