Originally Posted by dangalak
Agassi wasn't a great athlete. Connors is incomparable to the modern era. Chang didn't have great power either. Neither did Hewitt. Ferrer is strong, but his shots don't have explosive power either. Nalbandian has the power to do damage, but he also isn't a great athlete.
There are many different types of talent in the athletic sense, especially when it comes to tennis.
All of those guys hit far harder than their height would imply, Agassi and Connors especially. What all these guys have in common is incredibly strong trunks, good timing and great strength:weight ratio in general.
Connor's contemporaries included guys like Tanner, Ashe, McEnroe and the like who were all taller than him but could not generate the same kind of pace off of both sides.
Agassi's power is prodigious and a function of his father's Olympic boxer genes and incredible hand eye coordination. He emerged on the scene hitting harder off of both sides and earlier than just about anyone else in the sport.
Chang and Hewitt both could produce pace and crack winners. I'm not sure what anyone is saying about them being powerless. Both were evenly matched with the players of their day and could hit winners. Here are some examples of what kind of pace they can generate.
Ferrer and Nalbandian likewise have stout strength and would likely be able to overpower someone like Djokovic in a straight up lifting contest. That both can overpower taller men off the ground (like Davydenko) is a testament to their ability to time the ball and generate lots of torque into the shot.
What these guys have in common is that they are all unusually strong, have great hand-eye coordination and that allows them to be evenly matched off the ground with taller men.
These type of men are very rare, and that means that there will always be less of them than 6'5 guys who can rely on their length of limb to generate pace.