Great post, Rightnow!
I agree with you about stopping the run. The main problem with the 3-4 is that your D-line has to be great, every game. They just haven't seemed to gell, yet. Perhaps Payne's and Walker's injuries are bothering them more than they will admit.
The secondary doesn't bother me as much. I mean, it is hard to get down on them too much when playing the Vikings (who have the no. 1 offense in the league right now). Coleman is still learning the safety position, but his 102-yard interception/TD should give us a little faith in him. Robinson looks like he'll mature into a great player, but it'll take some time.
I think the main problem our defense has right now is pass rushing. We are giving the QB too much time to make his reads, and this puts too much pressure on our pass coverage. Opposing QB's should never have 5-6 seconds to make reads and they read again.
I'm on the fence about playcalling, tho'. I mean, the players have to execute! It doesn't matter what plays are called if the players make mental mistakes and don't block right or run the right routes or whatever.
You are right on the money about the good in our team.