Is a 67" ski the right size for a 150lb person? Sounds like a really big ski but I know it's a slower speed ski so maybe that's correct. Your bindings should fit pretty much any ski out there so don't let that persuade you towards any particular brand of ski's.
Like you, I've got a major course bug and I'm constantly looking to upgrade. My opinion is that people are dumping ski's in favor of the latest and greatest and you pretty much have all winter to look for a good deal so do you really want to stare at a brand new ski all winter?
In my experience, a forgiving ski is nice because I'm less likely to screw up. The problem with a forgiving ski is my feedback while doing something right or wrong is less obvious so it's harder for me to improve. If I get in the right pulling position on a high end ski, the acceleration is much more dramatic so when my eyes are the size of golf balls, I understand that's what I'm supposed to be feeling. On the opposite side of the coin, if I make a hard turn and can't hang on or can't make the ski turn, then my form is poor and I need to focus on fixing the problem.
To me, it's a lot like golf. When I played with forgiving clubs, I enjoyed it but could never figure out why I was so inconsistent. When I changed clubs, I realized that the clubs were doing all the work and the reason I was inconsistent was because my swing sucked.