I agree that the true test of the academy is whether it actually delivers the next Gerrard or Fowler. And there would be no question that Rafa was responsible for such success were he still LFC manager at the time. But he won't be; and that's essentially where I differ with you guys.
Rafa's already made as much contribution to the Academy as he can, did so under difficult monetary conditions blah blah, but got sacked as LFC manager before his "vision" (if it can be called that) could reach fruition. So all he can really be thanked for is getting the ball rolling (where before it was just a place that everyone essentially ignored in the blind hope that some kid nobody had ever heard of walked up to the gate one day and turned out to be a superstar without any real training).
So, my point is that although the Academy should be seen as Benitez's lasting legacy, its ultimate success rests in the hands of the people he appointed, and while he may claim credit for appointing them, the development of these potentially world class players is actually out of Rafa's hands. The success of the Academy is not the success of one person, and there are a lot of steps to go yet as you've correctly pointed out. Rafa helped us take that critical first step when no one else cared, yet you won't consider thanking him for the obvious improvements that step brought us until the journey of 1000 miles is finished. That just seems a bit cynical to me.
(Analogy: Would Kenny Dalglish be LFC manager now had Benitez not appointed him in charge of the Academy and as club ambassador? Probably not, right? While we've not achieved anything material, we have hope and unity where before we had neither. The point here is not that Benitez should be credited with the upswing in our fortunes on the pitch, but that small things done properly have consequences we wouldn't dream of. However, once we've dreamed those powerful dreams we often forget the small things that started them.)