Ive actually seen damn good athletes who struggle with proper squat technique and clean as well..
Anyways, gonna leave it as it is. Squat how you do and ill squat how ill do. I nor any athlete need to squat below parallel and vice versa. Again, im not talking about squatting quarter squats, i mean i favor thigh parallel squats for the majority of my training IE powerlifting depth(lower than half squat). And you obviously prefer deeper, so be it to each his own.
also, are you a big RIPPTOE guy? JW, like some of his vids, just cant get him over saying that VJ cant be improved.
If damn good athletes struggle with proper squat technique than their instruction is probably not up to par.
Regarding Rippetoe, I like that he makes clear predictions of what can be achieved with his program thus making it evaluable by everyone, I like that he wants things to be done right and does not just come up with some wishy-washy way of saying "do what works best for you", I like that he has good arguments why he thinks his method of training a beginner is the best, I like that he takes into account various stages of training advancement, which he also defined objectively with Lon Kilgore, and organizes training accordingly.
I think defining these stages the way he did along with his extremely detailed description and instruction of how to execute the basic barbell exercises and how to coach them are his most important contributions to the field. It's not so much his Starting Strength method that is so important, although I find it to be extremely good and I am sure that the modifications in the upcoming 3rd edition are going to make it even better, but it is those universal principals that he described and made practically applicable.
Regarding him and VJ: He never said that VJ cannot be improved. He said that it cannot be improved above a certain level, which is a rather obvious point to make. His suggestion or observation was, that it won't usually go up higher than 30% of the initial height. He therefore takes into account the genetic disposition of an athlete for this kind of task, in which he is doing right I think. The 30% are of course a somewhat arbitrary number and can certainly be disputed. But I think this might actually be a somewhat accurate approximation of what will be achieved on average. We all know some examples of people who increased their ability by more than 30% (mind you, we are talking SVJ here), but those are a minority.
I would not necessarily listen to Rip for advice on people who want to increase either sprinting speed or VJ, but he will tell you that himself. One should however listen to what he has to say about training for novices in general, which is his forte, and also about what he has to say on barbell exercises.
That does not mean that he is right and everyone else is wrong, but if you want to make up your mind about certain things you would be wise to read what he has to say.