It absolutely is unfair, but I have never claimed to be the most rational guy when it comes to sports, and neither have most fans.
The Mariners had probably the best baseball team of all time in 2001, and they lost a crapshoot of a playoff series that was a far smaller sample size than the 162 games in which they proved that they were the best team, but that doesn't make their not winning the World Series that year any less painful or a damper on the whole year.
Likewise, while I would love the best record-teams from the NFC and AFC to play a five game series to at least take some of the uncertainty out of who really is the best, and while I am sure that Seattle would acquit themselves wonderfully in a series like that, it isn't going to happen, and if the Seahawks don't win it all this year, the consolation that they would have won if they had x amount more games won't be much consolation to me at all.