Yeah, home field advantage is a pretty big deal...
By the time you get to this point in the playoff season, the accuracy of home field advantage is pretty questionable. Since the two playoff teams probably haven't played all of the same teams over the season, the standings are heavily influenced by how soft their schedule was for the year.
Instead of using the entire season W-L record, why not use only the records of the teams they have played in common? Especially if they have played each other already.
As an example, the teams that the Broncos and Patriots have played in common are:
Texans (both won)
Ravens (both won)
Colts (Pats won in playoff, Broncos lost in regular season)
Each other (Pats won)
So who should get home field? Even if you didn't count the Colts playoff loss last week and only included the regular season, the heads up game should matter more than how many soft teams there are in their own divisions (that they get to beat up twice) or the arbitrarily assigned season schedules outside their own divisions.
But honestly, even if they were playing in Foxborough this weekend, I'd still have the same seat for the game.