If anything I think Pittsburgh is not getting enough credit from the bettors, consider this:
At one point they were 7-3 with all three losses coming on the final play of the game.
Week 12 Roethlisberger has first game back after surgery and they get pummeled at Indy (which most teams did).
Week 13 they lose by a TD to a decent Cincy team
Week 14 beat a Chicago team that, at least then, people thought to be one of the favorites to be in Detroit.
Week 15 Beat Minny, no big deal as it turns out.
Week 16 Kill Cleveland in a shutout, again, no big deal.
Week 17 Beat Detroit, 4 must wins in a row.
Looking back on an 11-5 season that could easily been 14-2 considering the three losses on the last play of the game.
They go on the road and beat Cincy with Kitna having as good a day as Palmer would have, though some must think Plamer would have thrown for 500+ yards and demand his injury was the difference as he was also going to play linebacker and stop those 31 points the offense put up.
They go on the road and beat an unbeatable Indy team despite the best effort of the officials and now people say, well Indy wasn't that good or they were ripe for an upset.
Again go on the road and beat down the Broncos, who now weren't that good and were ripe for an upset. Amazing luck on the Steelers part that they kept running into teams that were over-rated and ripe for an upset at home.
30-7 in their last 37 games including playoffs.
Seattle gets a bye week, plays two games at home, Surviving against Washington and out playing Carolina in the process.
Do I think Pittsburgh wins this game? Well I hope so, obviously, but I see the two teams matching up fairly evenly. Seattle's offensive and defensive lines will pose trouble for the Steelers, no doubt. To say the wrong team is favored just doesn't make sense to me though, perhaps the line should be 2.5 or 3, but certainally not -4 for Seattle.
