[rypper11]

The regular season is absolutely meaningful. 32 teams. 12 get in. Top 4 teams get a week to heal and rest. The odds are stacked in the favor of the top regular season teams.
That being said, I like to see an underdog beat the odds and win it all. That's the beauty of a single-elimination tournament. NFL playoffs are the most exciting because the best team doesn't always advance, just the one who plays the better game that day.
Two things to consider about the 2007 Giants:
1) 7-1 on the road and 3-5 at home. Obviously the Giants didn't have an home-field advantage this year and were thus an enigma in football to begin with. Teams traditionally want to play at home and thus home-field advantage helps in the playoffs.
2) If the Super Bowl was played 7 times (as in other pro sport championships) the best teams would win every time. In this scenario, the Pats would have won at least 4 times, probably 5 or 6. Of course, if the playoffs were also series instead of single elimination they probably wouldn't have been in the Super Bowl.
So no, the playoffs don't need to be changed. If you want to remember who the "best" team was for the 2007, it was the Patriots. But the Giants get the ring and are the World Champions.
As for the "quality" of teams getting in (Giants in, Vikings out), this shows even more how important the regular season is. Sure, an easier schedule helps you get a better seed (we could have been 13-3 w/ Tampa's schedule and had a bye with playoffs at home) but unless we expand the season to 31 games with each team playing every other team once, there will always be teams with an easier schedule.