I'm sorry. In football, practicing "together" in a regular basis, as often as possible, creates more cohesiveness on the plays. Everyone gets better at doing their jobs, and players next to them, understand exactly how that player will perform. When it comes to timing, and anticipation of actions, between receivers and QBs, it's paramount. Thinking otherwise doesn't make sense.
The only way you mesh the reality of what someone will do, during a play, with another player, is by practicing that play repeatedly, so you know for sure.
In a practice, if you run the same play a half dozen times, you're not going to get a chance to go through the progressions, and the options within it, more than two times. As an example, on a passing play, with 3 guys out on routes. If you run it 6 times, you get a maximum of two reps for each of the receivers, and you haven't even touched on the concept with a TE or RB as an outlet. You also haven't developed the rhythm, based on the speed of the receivers, the time frame on the QB release, or any of the other factors that apply.
If I was to go by what some seem to believe, you don't need to practice together. You just need to know the plays. That's like saying someone who knows the rules of golf can just buy clubs and be a par golfer. Maybe take a few swings at a driving range first, because that's all you need to know?
No. Repetition is needed. Lombardi would roll over in his grave if he heard what's said about it not being necessary.
But, that's only my opinion. We're all welcome to our own.
Now, how could Rodgers be responsible for defensive problems. It's simple enough. If you can't control the ball long enough, your defense wears down by having to spend too much time on the field. A ball control game, where your QB is efficient, reduces the defense's exposure to number of plays they need to be out there. This is an obvious consideration in my book. You gotta think like a coach across the board. The entire game links itself to itself, regardless of what side of the ball we're talking about.