"Not even close?" B.S. We allow fewer yards, we have more fumble recoveries, more sacks and the same ypc on the ground. We allow fewer yards in the air per attempt and we only allow 3 more points per game than they do. I'd say it is pretty damn close. As was pointed out clearly in a very well written and researched article, the Cardinals are way over on the plus side in the luck column. Most importantly, it looks like their defense has weakened in the second half of the season while ours has clearly improved quite a bit.
As to toughness of schedule, they're opponents combined for a .547 record. Ours was .504. Theirs ranks 8th and ours is 13th, so not a ton of difference there.
Lastly, since you're fond of DVOA, our overall is #4. Theirs is #22. Look at the bottom half of those rankings and only one of those teams is in the playoffs, so the luck factor is most definitely there. That tends to run out in the playoffs. So again, I'm not particularly scared of playing them at Lambeau or anywhere else.