Pat Mac has a little too much to say given the limits of his wisdom. I suppose the talking heads in general are paid to second guess guys like Fed through their ups and especially their downs.
Roger has done a historic job without much of a coach, so it's odd for me to hear people say that he obviously needs one now. Number one... Number one in the world... For years...
If he takes on a coach, it will be someone he trusts. If that trust in a person existed for him now, he'd have that person in his camp I think. Keep in mind that Federer retaking the number one spot isn't entirely up to him. It could be the case that Roger, as great as he is, will never catch up with Rafa, even with a coach. The only thing that slowed Nadal down last year was the Mt. Everest of a schedule that he played. The Olympics aren't in the way this year and given that he's still improving, I wouldn't be surprised if Nadal completes the true Grand Slam of tennis perhaps this year or the next.
Right now I think that Rafa losing the top rung in the world is up to him and what he does to keep it.