Against JesusFed anyone would look fairly average. Djokovic would have been destroyed even worse had he (Djokovic) faced Roger in that semi-final.
And no, he (Murray) is not overrated. He's technically a better grass player than Djokovic is. Those three titles the Serb give him statistics on the surface than he does, considering he plays the same damn way he does on clay and still wins the title. Slow as fuck grass does that. It's the same for Nadal during 2006-11.