now that I've noticed the shoulder turn thing, I'm seeing it everywhere. I'm a big fan of those incredibly boring teaching episodes on the golf channel. The best golfers all turn their back fully. What I am sensing now is that if you don't really make that full shoulder turn, your legs can't pull your body through the shot - and you have no choice but to muscle your arms through the shot instead - which leads to all sorts of bad things.
Remember the little drums in Karate Kid part II? They spun them and little strings with beads would hit the drum face. That's kind like the golf swing motion. Your arms are really there to do very little, except provide a bridge between your club and your body, and act like a whip or flail. Once you put your arms in it too much, they stop being whip like, and start being more stick-like.
Hopefully I'm on to something here; I'm sure it will work for two rounds and backfire, as usual.
Sidenote - looks like Ken, Erik and I are going to play in a tournament at The Raven up in the mountains in June. Should be fun - I am excited to try and play under the pressure of competition. I have so far really let other people get in my head on the course; so maybe this is the trial by fire I need.