Holmgren laid a giant strategic egg...he cost his team this game. That's very hard, because he is a great coach -- he just wasn't great...heck he wasn't even passable, as a strategist, in this game.
Holmgren's offense game plan was poor...especially in the red zone, where he had been great with his plan all year long. It was Holmgren's game plan that allowed the Steelers to use the big plays to beat him. None of the Steelers players had any kind of a big game, and they weren't even as physical as the Seahawks were...imagine that!? They just kept there heads and played within themselves...and let the Seahawks beat themselves, for the most part. And most the time, that's how you get to be champions. For Holmgren....well, he SHOULD hang his head, it was his poor game preparation and strategy that was the biggest factor of the day. A terrible thing for any coach to absorb.
I don't think they were obviously the better team. They bit hard on two gadget plays and gave away a lot of 2nd half runs (not just the Willie Parker run, look at the Pitt possession after that). I think Seattle was obviously a very good team, but I don't think it's obvious one way or the other which team was better.
I think Holmgren's game plan was fine, they kept getting stopped because they kept botching it. They seemed to be able to get to scoring range nearly at will but just couldn't get the biscuit in the bucket.