Judging Vettel based on solely this year is as bad as judging him solely on last year. I would assume, or pretty much expect, the BBC to look at the bigger picture.
Even looking at Alonso, who in many people’s views is right now the god of driving. Despite his problems with the team, I don’t think many would make the point that he deserved #10 based on 2007, and while he had a couple of impressive races (as did Vettel this year), 2008 and 2009 didn’t show the Alonso we saw this year as well.
Why I listed Vettel above Alonso in my earlier list, I assume is why BBC (seems to) does it now. He is judged on the skills he has shown in the different forms he has had. He is judged on his blistering speed of 2011, he is judged on the way he has shown to learn from (almost) every mistake he has made, he is judged on how he performed when it was necessary in 2010, putting in the performance needed to win the last 4 races to go and win the championship. I believe he is also judged on what many people do not see, which are his often praised technical skills.
That I believe is the only way to judge a current driver in this context. By not looking at current form, as every great in history has had better and worse form seasons, but by looking all the skills and abilities this driver has shown throughout his career, and maybe to a certain extend extrapolating this to what we can expect of him in the future.