In actuality, there's an equal and opposite arguement for every scenario. So ultimately, I find it comes down to your gut feeling.
Example: Team A's Passing Game is horrible this year.
1. Team A's running game will be better because they have to run!
2. Team A's running game will be worse because defenses will be stacking the line.
Each can be validated over and over.
Just go with your gut. There is no absolute equation. Because if there were, then we'd all know about it by now.
Only 3 leagues this year. No sense in rooting for everyone in the NFL.