I agree that Nadal is very prone to early round upsets on grass and that's why his Top-10 record on the surface may be misleading. It will be interesting to see what his Wimbledon strategy is gonna be in the future.
Well,starting from 2015 with the one week extra of grass court tennis he will have more options.I guess he will take a week break after the French,play a tournament in the second week and pratice in London in the third week.
Now,just like in the previous years it`s always tough for the guys who play the finals at the French to have a good preparation for Wimbledon.They either skip Halle/Queens or go tired there and lose early.And playing in the second week(Hertogenbosch or Eastbourne) isn`t an option either.
So for Nadal,what happened this year was similar to every other year with the difference that he got through playing badly in 5 sets against the likes of Kendrick, Haase,Petschner.