Don't get offended, but the Lions haven't really proven they are capable of winning the division. It's more than head-to-head. I believe you're trending toward being the top contender NFCC champ, but it is correct to be skeptical, because, well, you're the Lions.
If you just look at who has been added and lost from last year, that's too literal of a way to look at it - how they are executing is the main thing. GB's been competitive enough to win all their games so far (but didn't win at Atlanta in a game they choked away) without their primary offensive weapons or line being intact, and making about a thousand self-inflicted mistakes. They haven't come close to their potential/ceiling and yet they're still holding their own - when they get people back and clean up the mistakes, they could be formidable.
No offense taken.
If we are only talking this year, then neither team has
really proven they are capable of winning the division (though Chi and Min have proven they definitely will not). It's still a small sample size.
That being said...
According to PFF:
Det - 2nd in Offense, 17th in Defense, 17th in special teams. 72 points for, 63 against
GB - 21st in Offense, 13th in Defense, 29th in special teams. 80 points for, 62 against
GB opponents to this point are a combined 4-5
Det opponents to this point are a combined 6-3
Both teams sit at 2-1 with some key pieces missing.
From that perspective, I can see your argument for why this game will be more informative as it relates to the NFC North than recent history. The two teams appear to be more alike at this point than they are different.