Well, there are very few members that can remember back as far as I can - but I have done the "whole release thing" in the past (from 29 through to 45 in consecutive classes over a 4 week period).
What I love about mixing is that you can define your own class and as an instructor I can push my members to do different things.
What's wrong with doing a class of all super hard tracks? Or all the easy ones for that matter? Have a class where you load up the squat weight and then use zero weight on the toughest lunge track ever to push hard on technique.
As an instructor, I'm there to guide my class toward improving - increasing their weight, getting better...if they want to. Then again, some people just come along for the fun of it! There's no right or wrong way here - except for those instructors who don't ever mix it up because, quite honestly, they're just too lazy to learn something new. No excuse for doing a release for the full 3 months in Pump.
I remain unconvinced that there's any particular training method designed for individual releases that will make a significant difference. At one time you could see a defined theme of choreo running through some releases (look at BP33 to see how they used held moves - 1/3 in squats, holds in biceps, triceps and abs)... but newer releases haven't had this type of theme.
What tends to happen more in Pump is that a different move comes along and we see it used ad nauseum over the next few releases...