Rafael Nadal might have the most to gain from another Wimbledon title. For starters, it would be his third French Open-Wimbledon combination in the same year, something that only Bjorn Borg accomplished—three consecutive years, 1978-80.
For all of the questions surrounding the past two years on grass, a third Wimbledon title would wash them away. He would be in the three-title club at SW19 with John McEnroe and Boris Becker, who basically became kings for their exploits at Wimbledon.
More historical prominence: Nadal would have at least three majors on two different surfaces at two different venues. If we also combine his three hard-court titles at Australia and New York, that would place him as the only player with the triple on three different surfaces altogether.
(Side note: Currently, Roger Federer is the only player with at least three majors at three different venues, although he did not do this on clay for the true third surface. You can compare the unique nature of this achievement in a fairly confusing article written two years ago about dual-surface masters.)
Nadal would also close his career majors gap behind Roger Federer, which would be 17-15. It would mean reducing his deficit in half within one month, and it would all but give him greater odds to be the man with the most in history by the end of his career.
It would also signal the full-fledged reality that a healthy Nadal can still win majors on all surfaces, and it would tighten his grip on the No. 1 ranking heading into the North American hard-court tour.
Nadal would also gain his fourth year of multiple titles with a shot to repeat his 2010 Northern Hemisphere major sweep from Paris to New York. He would clinch the player of the year whether or not he won the U.S. Open or finished with the No. 1 ranking.
The French Open-Wimbledon combo is enormous and certainly ranks above another player (unless it was Stanislas Wawrinka, who already has the Australian Open title) finishing the year by winning the U.S. Open, the remaining Masters and WTF. And maybe Nadal would snag more of these other titles as well.
A Nadal win at Wimbledon would probably generate at least a few more articles and a handful of commentaries for tennis fans to discuss. That's not bad for tennis or Nadal.