The 1984 Seahawks secondary was pretty damn good. They made Marino look bad in that playoff loss.
I grew up watching the 70's Steelers and Raiders. My dad was a Raiders fan before the Seahawks existed, since he's originally from the Bay Area. I remember watching some sports special where members of the Steelers defense were being interviewed in a restaurant. They were all eating pasta, drinking whiskey and beer, and smoking cigars. Pro football athletes in the 1970's, and especially that Steelers defense, were like a bunch of big blue-collar thugs, but they wouldn't even be competitive as athletes today.
Today's athletes (especially receivers and skill position players) are genetic freaks. They're bigger, faster and stronger than anything those defenses ever saw back in the 1980's and before. I once heard Jerry Rice say in an interview that Calvin Johnson would have absolutely destroyed defenses back in the 1980's, that he is such a freak that he would have eclipsed Rice's numbers easily. I'd agree with that.
You put any of those historical secondaries against the offenses the Seahawks faced this season. Especially Atlanta in the playoffs. They'd have been killed. Can you imagine Julio Jones and Roddy White teaming up on Dick Lebeau and Night Train Lane? That would have been comical. They'd be out there huffing and puffing and getting their asses handed to them on every down. The NFL was different back in the 70's. It was mostly a lot of run game with pretty basic passing schemes. It wasn't until Bill Walsh came into the NFL and invented the WCO that offenses really started throwing the ball much, or using any kind of advanced schemes. Tom Landry, maybe.
But still... the point remains the same. There is no way any defense from the 1970's steps into 2012 and plays competitive. They didn't even understand proper nutrition back then.
Now imagine the Legion of Boom playing back in those days. Being allowed to hit defenseless receivers, hit guys in the helmet, hold as much as they want until the ball leaves the QB's hand. Can you imagine? They'd have killed people. Richard Sherman would have been faster, bigger and stronger than anyone on the field outside of his own secondary. Especially back in the 1960's. It would have been ridiculous. Heck, Kam Chancellor is faster and stronger than any member of the Steel Curtain ever was. I watched those guys play. Yeah, they were big dudes for their day. But they were slow and ridiculously out of shape compared to modern athletes.
And imagine if the Patriots, Packers, Falcons or Saints could play in the 1970's. Ridiculous. It would have been a bloodbath. You'd have seen 700+ yard passing games. Brady would have destroyed that Steelers defense with ease. Aaron Rodgers with average modern WRs would have killed them. Can you imagine Matt Ryan w/ Jones and White going against that defense? Matt Stafford and Calvin Johnson? Those are all teams the Seahawks played last season and our secondary shut them down, without any of the advantages those 1970's defenses enjoyed when rules were tilted in their favor. Even playing with 1970's rules, can you imagine Calvin Johnson going against Ronnie Lott? He would have jumped over him with ease, outran him on every down, juked the dude out of his cleats.
Too many people romanticize those older teams. Those guys weren't even athletes by today's standards. Hell, even Kenny Easley would have got his butt handed to him by today's smarter QBs and stronger, faster WRs.
Anyway... just a few thoughts. It is fun to imagine it all though. It would be so cool if you really could match some of those teams up. Mid-80's Niners versus 70's Steelers. Early-90's Cowboys versus Mid-00's Patriots. Ronnie Lott vs Calvin Johnson. Kenny Easley vs Roddy White. That would be awesome.