It was not a negative per se. I said their d is bad on top of having a new system to learn. Their D is bad is the reason. If they had talented players this wouldn't be a concern. They don't. Yes, the Bears offense won't be as good Sunday as it will be in December and the same can be said for their d. Except, we have a lot more talent.
Their defense was 28th in total yards, 31st in yards a play, 28th in points allowed a game, all while being on the field the 8th least and acquiring almost no one to upgrade it.
EDIT: I messed up this post big time with regards to Packers stats last season. In my haste I reopened NFLs defensive stats and it was set to 2018 preseason. Here are the numbers in those categories last year:
22nd in yards a game, 24th in yards a play, 25th in points a game, and they were on the field 26th most.
I thought I'd leave the old Post up so the mistake is transparent.