I've been playing/watching tennis for more than 35 years (my knees and ankles remind me about that everyday
). I only saw Laver towards the end of his career and he was great then as well. If the sport had been open then and Rod had been able to play once he went pro he would be the one with all of the records.
My favorite all-time player is Bjorn Borg. What a solid game and I loved that you could never tell if he was winning or losing----a great weapon vis a vie wearing down your opponent, IMO.
For most Americans, the peak of men's tennis was the foursome of Sampras, Aggasi, Courrier and Chang---four guys that came up together and pretty much dominated tennis as a whole for years. Yet, Americans didn't watch that much more tennis then than they do now.
I think that Aggasi has been the favorite tennis player for most Americans over the last 25 years because he had both personallity as well as ability. Plus, he 're-invented' himself later in his career and had great success.
Tennis is one of those games that, if you haven't tried it, you don't really know how hard it is. Most guys play some baseball, football, basketball as kids. Even if it's just Little League, you've experienced what it takes. I don't think that's true of tennis, although I do think that's changeing.
These guys play 4 hr + matches and leave their guts on the court---sometimes litterally. They have body cramps, twisted ankles, torn ligaments and shoulders that cry out in pain. On the pro level this is not some cute country club sport---it's a major physical test.
Equipment has also changed the game. Almost no one 'serves and volleys' anymore. New racquet technology has made groundstrokes a major weapon with the speed these guys can hit the ball. In the early 80's a guy I played with developed the first battery powered ball machine. As part of his business plan they tracked the speed of balls on groundstrokes. It averaged 55 mph on the pro tour. Yesterday many of the ground strokes were in the 80-90 mph range. And even though the serves have also gotten bigger, the ability to strike the ball cleanly with these new racquets has partnered with the speed to make coming in behind a serve a tough play.
I agree that Roddick has been a disappointment. But people look at that serve and think he should win easily. Refer to my point above. The problem with Roddick is that the rest of his game, while solid, isn't exceptional, unlike the guys above him that he consistently loses to. He's either going to have to improve the rest of his game (which I don't think he can do), his fitness (which he reportedly did this winter but it didn't help against Federer) or he's going to have to change his tactics (like take a chance and be the only true serve and volley guy out there).