I'm trying to think here, and I think to be in the "mix" you have to be a team that wasn't a chalk pick, so they'd have beaten at least 2 teams that were "considered better" entering the playoffs.
I think the contenders of the last several years might be:
2005 Steelers -- beat Bengals, Colts, Broncos, Seahawks
2001 Patriots -- beat Raiders, Steelers, Rams
1997 Broncos -- beat Jaguars, Chiefs, Steelers, Packers
I think there's a big gap before 1997 where the NFC was so dominant that a top 2 NFC team was always the chalk pick and they always won the Super Bowl.
So if we're ranking the
schedules of those three teams + this year's Giants, I might rank something like:
1. 2007 Giants
2. 2001 Patriots
3. 2005 Steelers
4. 1997 Broncos
The 1997 Broncos had a tough "on paper" route, but they had a better record than 2 of the teams they beat and won against the Chiefs possibly because they started Elvis Grbac and not Rich Gannon.
The 2005 Steelers had a lot of road games, but you could argue that they were better than both the Bengals and the Broncos in 2005 and would have been the #2 seed if not for Big Ben getting hurt. And the Seahawks, bad calls and all, were a poor Super Bowl opponent.
The 2001 Patriots benefitted from having to play only 3 games, and while they did beat two heavily-favored playoff opponents, one of them was QBd by Kordell Stewart who, while in my opinion is underrated on the whole, simply wasn't a great big game QB.
So I think you could make the case that these Giants, in knocking off the top 2 NFC contenders + the undefeated AFC team, just played the toughest playoff schedule in the last couple of decades.