My older boy did Air Alert and got decent results, as I recall.
That said, this question comes up on a lot of BBing type forums, and I think that you guys are spot on. Kids want to jump high without first establishing a strength base.
If you can squat 300-400lbs and can't jump, then it's time to work on plyos, technique and the like. For those who don't have the book that style referred to,
here is an interview with Kelly Baggett. It mentions that he improved his vertical from 23" to over 42". Depending on the trainee he might emphasize different things. But about the need for a strength base, I find a small excerpt from what Kelly says to be interesting:
<div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">
•The most explosive athletes are strong.
• The average high jumper at 6'4 165 lbs, even with legs as skinny and as long as a waterhose, will still squat in the upper 300's.
• The average national-class olympic lifter has a vertical in the high 30's and some 300 lb heavyweights even have VJs over 40 inches.
• A sprinter will VJ 40+ and squat 2.5 to 3 times their bodyweight easily.
• The average national class shotputter at 260 lbs + can broad jump 10 feet or more.
• Kobe Bryant routinely does squats with over 400 lbs + chain.
</div>
He also mentions a stat about the average linebacker prospect at the NFL combine has a vertical 6-8"
more than the average NBA prospect despite weighing a lot more, and attributes this to the emphasis on strength training for football players.