Well both Federer and Murray are obvious difference makers. In Federers case everyone knows that only one man has been able to stop him from the semi in 24 slams (he had 23 consective GS semis) is Soderling. That's a sick 6 years of slams!. So he is dangerous for everyone except the top2 that can get him until the semis. Same with Murray. Top2 can't get him until the semis. Thinking all the way until the semi already is crazy. Anything can happen and the 4th Round/QF will be big rounds to get through.
The real big difference makers are seeds 5-8 with some very dangerous players. The QFs will be the most critical matches. Top4 likely want to avoid Soderling considering his history in the tournament. Ferrer is also dangerous considering his form this season.
I'm not switching from my prediction that one of Rafa and Djokovic will go out in the QF or earlier