I'm generally interested in the rules of all games -- in particular, in the "best" set of rules, that will make the game the most fun to watch or play, or most likely to pick a worthy champion, according to the goals of the contest. Those of you who have watched Wimbledon over the years won't be surprised by what I have to say: the game (on the men's side) would be much more fun to watch if the serving weren't so dominant. I (and others) have thought this for years; I was reminded by having just viewed what is probably the most extreme set ever played in this regard. In the 4th set between Ivo Karlovic and Jo-Wilfried Tsonga, they reached 6-all with the servers losing only one point combined! That's 24/24 for Karlovic, 24/25 for the comparatively pathetic serve of Tsonga. They must have choked up under the pressure of the tiebreak, because the 6'10" Karlovic actually lost a point on serve (by missing an easy volley) and Tsonga lost two, Karlovic taking the tiebreak and the match 7-5. Too bad, it would have been fascinating to see how long the 5th set (with no tiebreak) would have lasted! (Note: Just before I tuned in, Karlovic had in fact won the 3rd set with the only break of the match.)
Well, it's clear the game would have more suspenseful moments for the fans, as well as putting more of a premium on a variety of skilled shotmaking by the players, if the serve weren't so dominant. Of course if someone wanted to fix this, it's not hard to think of proposals such as shrinking the service box or, even more extreme, allowing only one serve. There are reasons, of course, that this is very unlikely to happen. For one thing, the current top players have mastered their craft under the current rules, and I suspect they would hate the idea of any significant change. For another, the current rules work fine for casual players, and it would be inconvenient to have different rules at all levels other than professional (I admit that even as a *very* casual player, I liked the idea that I was on the same-shaped court with the same rules as the pros.)
Something that can be done without a revolt is to tinker with the surface, and in fact Wimbledon did this a few years ago, so a backcourt game is more viable there than it used to be, and returners have more of a chance. I find the improvement in watchability to be generally quite noticeable. Also possible is some restriction on rackets -- I've heard this is politically very difficult because of the sponsors, but golf restricts the clubs, so maybe it's not impossible.
By the way: a very modest rule change that players might not find too jarring would be to make all serves that hit the netcord faults (as in volleyball.) No one aims for the netcord, and it's basically luck when it drops in for a let anyway, so this leaves the game relatively unchanged while decreasing the server's advantage by a smidgen.