You ask a lot of very important questions. Since I have been following Brian (circa 2003 or 2004, maybe earlier actually) - I feel the central thesis to his teaching (again this is my opinion) is to:
Fix the Face.
I think most golfers know how to compensate based on their face issue(s). That is to say, when I see the average Joe beating balls on the range or on my Tuesday night (golf league night) play their setups, stance, grip, and so are designed to compensate for the (in most cases) open face.
I have been playing for 20+ years (I am 30) and have had every golf problem known to man. Lately, through my work with Damon, Brian, and Kevin Shields (Jon Hardesty too) 95% of my problems are with the clubface. If you have seen NSA, Brian spends considerable time discussing where, in the swing, one can have problems with the face. That is to say you can fan it open on the backswing, loose twistaway on the downswing, have improper swivel (need for wedding ring up) and so on.
When Kevin Shields examined my latest Trackman numbers at the GTE seminar, the values were much improved. However, in all three swings we looked at, the face was open. As a result, many of my flaws in the swing were built around a fear of losing the ball to the right. I seem to suffer from a few things that creep in at random times: pop out, and overly rotated left arm, and a failure to main twistaway.
All are very important, but of the three, maybe maintaining the twistaway is the most critical. Kevin told me that you cannot get around this issue. If I want to get better, get into more solid alignments, have more delay, more lag, I need to learn how to maintain the twist all the way through.
The hard part, or should I say really frustrating part, is that I have known this for quite some time. Yet the diagnosis and drills to fix this problem aren't all that difficult to find and apply. Granted, I do make a concerted effort to maintain the twist with the driver (my biggest problem club) and I always thought if I perform too much twist away, I'd hook the sucker off the planet. As Brian correctly pointed out to me on the range, with the longer clubs, the tendency is for the club to open. To counteract this unwanted twist (or torque), I need to apply a lot of twistaway. This was maybe the most eye opening swing thought and analysis I have come across in my 20+ years of hacking this little white ball. Though I think Damon and Kevin Shields also picked this up, I was fortunate enough to have Brian put it into terms I could finally grasp.
In summary, you might have to take a step or two back before you can finally move forward. I thought I knew my swing inside and out. But what I really know, is how much I don't know. Or stated differently, I am still overcoming a lot of bad swing advice and/or self-destructive thoughts that are preventing me from moving forward.
Erik