I'm cautiously hopeful about Jets' chances vs Steelers. Rex Ryan knew Steelers well, since as a DC of Ravens he has to plan against them twice a year. Steelers' weakest link is probably their OLine, and perhaps Ryan's blitzes will be able to catch Big Ben off-guard, even though he is quite mobile and very durable. Steelers have great defense, but they are better against the run and aside from Troy Palomaru, their secondary is suspect. Therefore, the key for Jets to beat the Steelers may lie with Sanchez's performance. If he can exploit Steelers' secondary and open the game up for their rushing attack, I think Jets may be able to pull another upset on Heitz Field. Big Ben is an elite QB, but after defeating both Manning and Brady, I think Jets have what it takes to take down another great QB.
As a complete non fan (and hater) of the Jets, you'll be fine. I've seen this a million times in sports. This is something not unlike the Colts in '06, or the Raiders back in the 70s. I doubt you'll win the Superbowl if you have to face the Packers, but I have no doubts you'll beat the Steelers. I'm sure one of them will complain when I say this, but Ben is not in Brady and Manning's league. People in Pittsburgh make a big deal out of him frequently, but it's been his defenses and Troy Polamalu whose been the lynchpin of the team (also Hines Ward). They are
supposedly the best defense in the NFL this year, however, like you mention their secondary is weak. Also, as you say, Sanchez will be a factor.
Here's the thing though, when I think intangibles, which are a huge factor IMO, I see the favor going to the Jets. The reprocusions of losing for y'all are pretty huge. One if Sanchez performance costs you the game (say interceptions for example), it'll demolish the confidence you have in him next year. In the Patriots game the O-Line and offense really rallied around Sanchez, so if he throws the game it'll really violate a lot of that effort they've put forth for him. I doubt he'll do that. Furthermore I think Rex Ryan realizes his accomplishes thus far will be forgotten if you loose this game. If the AFC divisional round proves to be his achilles heel yet again I doubt you'll see the visage of confidence you saw this year. If he loses this year, he'll much rather it be in the Super Bowl, since at least then he'll be graded on improvement. Bringing an AFC championship to the Jets is accomplishment enough for a second year (as I say I think the Packers have the edge if they go).
Overall y'all will be too much for the Steelers. They're secondary is suspect, and most of they're season, for better or ill, has been spent trying not to self-destruct. They've won games on dropped passes (Bills), questionable calls (Falcons) and I'm not sure they'll admit it, but the Ravens HANDED them their last victory. Flacco makes his traditional post-season blunders after nearly pounding the Steelers D into submission. Maybe that kind of victory is eye-openning to the Steelers. Maybe they'll mind their Ps and Qs next week, and maybe their experience with Rex Ryan defenses will be just enough to help them, but I doubt it.