Don't take it personally, but they have to be one of the most overrated teams ever. I mean, they have got such a big lead in points by playing A LOT (actually, no other team have played as many tournaments as them this year) and being regular but nothing like great...
Having played a total of 16 WTA events so far this year, they have reached JUST 5 finals (winning all of them, yeah) but none of them Grand Slam finals which sounds a bit of a joke. Specially when you see no other big teams commited enough or simply not good as them -in theory- and still they manage to lose against players not that extraordinary.
Safina has played 14 tournaments so far this year, playing 8 finals (winning 3 of them) but still she played in 2 GS finals and she is still getting the harshest treatment.
Black/Huber is a fine combo, surely the best these days (the best who takes doubles seriously, of course) but nothing extraordinary, believe me
This year in the slams, no they haven't reached a final but they are the only team to reach the QF's or better at all of them. And unlike Safina, they are current grand slam champions (USO) so I don't think that's a fair comparison. Safina wouldn't get any of the treatment she gets from some people if she had won a slam. Plus in singles it's very close at the top, and we have Serena with 3/4 slams. In doubles, nobody is near Black/Huber, it's not even close, so they shouldn't get any bad treatment because there is no other team that "should" be no.1 (like people say Serena "should" be no.1 in singles).
Now, I do agree that in 2009 there haven't been as many threatening teams to them as before but that's somewhat due to the many switches that take place. Peschke/Stubbs were good together in 2007 and beat Black/Huber twice but it didn't last and 2008 was a worse year for them. Raymond/Stosur were the previous no.1 team but again 2008 was not their best year. So we have the changeups in 2009 and Peschke/Raymond or Stosur/Stubbs are still very new. Wheras Black/Huber now have 3+ years of experience which gives them a HUGE edge. But it's not their fault they're the only team that lasted. As for people not taking it seriously, the majority of the top 10 are doubles specialists so of course they take it seriously. Plus we have many singles players who commit and stay to play doubles (like Williams sisters who have re-commited to doubles for the first time in years and stay in tournaments even if it's just to play doubles like Serena recently in Stanford, or Medina, Radwanska, Azarenka, Zvonareva, Llagostera, Martinez etc. etc.).
So yes, they have not been the most impressive in 2009 (although still very good!) but just look at their 2008 and 2007 seasons. In 2007, they made the SF of 21/22 tournaments, winning 9 incl. 2/4 slams. In 2008, they won 10 titles from 14 finals. And in the process seeing off many great teams, many of which have had to change because they weren't beating Cara/Liezel in the first place. They are well on course for a 3rd straight no.1 year which makes the late 2000's the "Black/Huber era" if you like, which puts them as one of
the all-time great teams and IMO they are "extraordinary"
I might go overboard when celebrating their victories but I don't think I'm overrating them as in saying they're the best ever or anything like that. There are obviously teams that have been alot better like Fernandez/Zvereva, Navratilova/Shriver, Vivi/Paola...