I am working on something more comprehensive, but have a few initial thoughts.

Atlanta has a better running game than Green Bay? So what. What does this Niner defense do? STOP THE RUN. It's in their DNA, it's who they are.

What does Atlanta have a hard time doing? STOPPING THE RUN. They gave up 123 yards to Seattle. They ranked 11 out of 16 NFC teams stopping the run (12th in total defense).

It's going to boil down to the basic formula for success: run the ball, stop the run, get after the passer.

Add the extra running capabilities of Kaep... looks pretty good to me.