The Racquet Scientist: A Fifth Grand Slam?

I can still remember the days when the idea of having a fifth Grand Slam tournament was percolating in the minds of promoters, pundits, and players, mainly for two reasons: It seemed a shame not to end any given year with a final, full-on major, and second, the percentage of indoor tournaments (remember when there was a surface accurately called “carpet,” as opposed to today’s “indoor hard”?) was much higher than it is today.

One of the more vocal “fifth slammers” was John McEnroe, whose prowess indoors, especially on fast carpet (which pretty much meant “all carpet”) rivals Roger Federer’s superiority on indoor hard courts today. But I don’t think Mac’s lobbying efforts were driven purely by self-interest.  
It made sense to barrack for a year-ending indoor major to round out the theoretical parity of surfaces: Roland Garros was the world championship of slow clay, Wimbledon the ultimate test on fast grass, the U.S. and Australian Opens a trial on medium to fast hard courts. Indoor carpet/hard had no major representation; a fifth Grand Slam would acknowledge the importance and unique nature of indoor tennis and—as a terrific bonus—end the year on that elusive and undoubtedly useful high note.  
The latter part of the idea was especially attractive, as the tennis year for most of the Open era tended to more or less peter out after the U.S. Open, only to enjoy an indoor revival come true winter in the northern and western hemispheres, where tennis was not just fashionable but popular and profitable. The explosive growth of both talent and interest in the game gradually changed all that, but not before the ITF made one bold attempt to create that fifth major in the form of the Grand Slam Cup.  
The lucrative Grand Slam Cup was launched in 1990 and expired in 1999. It originally offered the winner an incredible (for those days) $2 million payoff (McEnroe famously criticized the tournament for offering—get this—too much prize money), but it did not offer the typical Grand Slam format. The draw of 16 was based on Grand Slam performance; a sound idea subverted only by the small size of the field.  
The Grand Slam Cup was quite accurately seen as an attempt to stake out the “fifth slam” territory before the developing ATP season-ending championships (now know as the ATP World Tour Finals) beat it to that punch. For that reason, the ATP initially did not recognize the event, and by the time it did, the Grand Slam Cup itself was teetering—no more able to get over that “major tournament” bar than the various versions of the ATP’s own year-end bash. Neither the defunct Grand Slam Cup nor any of the ATP’s season-ending championships were embraced by anyone as a fifth major for the simple reason that neither one was that—a Grand Slam event being first and foremost a two-week, 128-draw, open event.  
Talk of a “fifth major” has died as sure a death as the outcry over the unacceptably fast speed of Wimbledon’s grass courts. I think this tells us a few interrelated things: The players, particularly the all-important top players, don’t want a fifth Grand Slam; they believe their plates are already fully loaded. Also, the Asian/fall circuit has emerged and continues to mature; there’s just no gap in the calendar right now. And the ATP World Tour Finals/Davis Cup combination in November brings the year to as satisfying close as you can expect, given the calendar.  
But here’s an idea that might address some of the more legitimate reasons for ending the year with a Grand Slam tournament: Convince the Australian Open to move back to its original slot as the last major of the year, but play it earlier in December, or even late November.  
I know this is one of those “when pigs fly” propositions. Tennis Australia is deliriously happy with the way it has re-invented its once deeply troubled event. But it’s still an appealing idea to play a major at or very near the end of the year, and doing so would certainly give the players a more sensible structure—in what other sport are the most significant events over three-fourths of the way through the year?—as well as a much longer and more natural off-season.