Well, I'm a Murray fan too among other players. True, Fed is my favorite, but I usually root for Murray in his matches against almost anyone. That's said, I think this IS Murray's style of play. It's not a bad thing, and I don't think Fed meant it as a bad thing, but rather he questioned whether Murray will be able to play that for a long time, since this style is harder on the body.
Plus, having watched many Murray matches over the years, I do think he is not very comfortable with the aggressive style of play. He often goes back playing defense because he's more comfortable like that. I'm not sure he has the tools to be agressive as well. Sure, he has the serve, but his strokes aren't as powerful as most other players IMO. The beauty in Murray's game is that he is a great thinker. He knows, most times, to hit the right shot at the right moment.
In the Nadal/Murray match in Monte Carlo, Murray tried to play Nadal's game in the 1st set. It was a total failure. He tried to hit moonballs to Nadal trying to force errors. By now, Murray should know that the only way to play Nadal is being aggressive. Murray did became more aggressive in the 2nd set of that match, but it was too little too late.
So yes, Murray's defensive tactics work wonders against Federer. However, I'm not sure Murray will do as well against other players who are not as easily frustrated. I think the loss at RG is a direct result of that tactic. If Murray does change his tactics against certain players, and keeps his game more efficient I think he'll be even more successful. Beating Fed is not the only goal out there - you actually want to win a slam too, and so far I'm not yet convinced Murray can do it.
