I don't like Murray's tactics.
He is too negative. This is okay against poor players, because they will make plenty unforced errors, so just waiting for them to make a mistake is an okay option.
When playing against top players, though, he needs to up his game and actually beat them; not wait for the opponent to lose the game.
This often starts from Murray's rather mediocre serve. He doesn't make many first serves, so he doesn't win a lot of cheap points, so a decent player will always have a good chance of breaking him a few times over the course of a match.
In rallying, too, he isn't aggressive enough. Far too often Murray will hit a good shot to get on top in a rally, only to fail to move into the net or fail to hit another big shot off an opponents defensive chip, so he lets them back into the point in a way that you wouldn't catch Federer doing.
I don't know if Murray needs a new coach or what, but until he changes his style a bit he won't be able beat the best in the world when it really counts. He might win a Grandslam event, but just now it looks like he will need to keep getting to finals in the hope his opponent has a nightmare, because he doesn't look like stepping up his game and winning otherwise.
All this is rather frustrating because I have seen him play aggressive matches against Federer and Nadal in the past and has deservedly beat them. I don't understand why he isn't so aggressive in the big tournaments.