I don't think the 1hhbh is making a comeback necessarily, but it is true that often, players with 1hhbh's take longer to mature. Federer is an example of this. His ATP career began in 1998, but it wasn't until 2004 that he finally reached a year-end ranking of no.1. It is a more difficult shot for most people to master than the 2hhbh, but if a player is able to develop it over time, the rewards are great. Of course for most young and up and coming players, the 2hhbh is the way to go, as it is easier for yougsters to wield, and is easier to develop consistency with. That is why so many of the young "prodigies" of tennis possess 2handers. But perhaps what we are seeing is the arrival of a wave of 1hhbh players that are finally coming into their own this year. Thre players with 1hhbh's have broken into the top 10 this past year for the first time : Blake, Ljubicic, and Robredo. Their ATP careers began in 1999, 1998, and 1999 respectively. Interestingly enough, Gonzo and Acasuso both have reached their peak rankings as of yet this year, and both also began their careers in 1999. Tommy Haas began his career in 1996, and reached a career high ranking of no.2 in 2002. Gaston Gaudio began his career in 1996 as well, and reached a career high ranking of no.5 in 2005. Perhaps, 7-9 years is around how long it takes for players with 1hhbh's to reach maturity on the ATP tour?
In contrast, this past year, we have seen the likes of Roddick, Hewitt, Safin, and Coria, all with 2-handers, take nosedives in the rankings (in the case of Safin, you could argue that injury was the prevailing factor). Roddick began his career in 2000, and was no.1 in the world by 2003, but has dropped to 11 now. Hewitt turned pro in 1998 and found himself atop the ATP at no.1 in 2001, and is currently 12. Safin turned pro in 1997, and reached no.1 in 2000; currently he is 77. Coria began in 2000, and reached a career-high no.3 by 2004, but has plummeted to 42 this year. Nadal, Baghdatis, Berdych, Djokovic, Murray, and Monfils are all 21 or younger prodigies with 2-handers that skyrocketed in the ATP rankings from day 1, reaching the top 20 or 30 in anywhere between 1-3 years...will be interesting to see where their careers go compared to Gasquet and Almagro for instance.