Wow, Mad Jock that is an exceptionally perceptive post!
This Christmas break has been my first break since starting intsructing a year ago and its interesting to look back and agree with everything you said! The sick days for interviews make me laugh - you are right, a friendly boss will be informed before hand but a pain in the butt boss will not.
A very good point about having a broad range of instructor experience if poss. Having a bunch of 1000 hr instructors positively itching to move on can't be good for the business!
If only I got paid for moaning at work I'd be a millionaire!