Federer is the greatest tennis player who has ever lived up to this point, a truly wonderful human being and a credit to the sport. However, given the current state of his game, can he beat the very top tier players? Unfortunately, no and here's why:
1. Ground strokes: Fed was able to compete with the really big hitters not because he has their natural power, but because his amazing reflexes allowed him to take time away from his opponent by taking the ball early. He has slowed down a nano second. That's all it takes at this level.
2. Consistency: At 29 you just can't stay at a consistently high level throughout an entire match. Due to the precise nature of his game, even at his best, Fed's margin of error on his swings was very small. Now those bad patches are coming more frequently and lasting longer.
3. Serve: The importance of Fed's serve in his overall play is huge. When he was at his best, he was Sampras like. Easy points at the most critical junctures in a match. No more.
4. Backhand: It's tired now and breaks down.
6. Mental Game: The mental pressure on a tennis player during a game is intense. The reason why tennis players generally go downhill after 27 is not due to physical decline. It's because you start to lose you ability to maintain that mental acuity throughout the match. In slang terms, it's called burn out. Think of all the pressure situations Fed has been in since he started playing tennis.
5. Competition: Nadal, Djoker, Del Potro,are monster players. Tough time to be 29.
The men's field in tennis is so deep that it won't matter if a draw opens up. Hope I am wrong.