Effective Leadership & consistent Blind Obedience are the main ingredients for "Destructive Cults".
Most Elders here, know only to well, that the "avg" JW is far from being consistently obedient.
I think you may be missing the point, and furthermore I disagree (so there! )
"Destructive cult" leaders lead by intimidation, by instilling fear, by emotional manipulation. Those are NOT qualities of "effective leadership".
The easily intimidated, the fearful, and the emotionally weak indeed do often "obey blindly".
However, JWs have progressed to the point where the majority of their enrollment are "born into it". There are many 3rd, 4th, even 5th or 6th, generation JWs out there. Their demographics have changed markedly from 50 or 60 years ago.
Just because one happens to be born into a "destructive cult", he is not by definition easily intimdated, fearful, or emotionally weak.
If JW leaders were effective, i.e., if they chose some other method than browbeatings and veiled threats, they would not have the problems they do with:
-- 80% or more of their kids leaving
-- huge numbers of their flock leading "double lives"
-- lack of cash flow (JWs tend to express in their dissatisfaction in ways that are not easily traceable - shutting your wallet is quite effective)
-- fewer and fewer of the "brothers" desiring to reach out for more responsibility
A "destructive cult" which demands "unquestioning obedience" can get away with it for the first generation or 2. Thereafter, the cult has just a few tough options: (1) Go out in a "blaze of glory", (2) fizzle into obscurity, or (3) drop the weird stuff and go "mainstream".
JWs became destructive during Rutherford's time. A generation or 2 later, they tried for a version of "blaze of glory" with their 1975 predictions. They had a chance to go to option 3 during the late 70's, when Ray Franz & others who were reform-minded had influence. But of course all that was quashed in the early 80's.
Ever since then, JWs are stubbornly clinging to their beliefs and methods, while the world passes them by. Every day they delay taking decisive action brings them closer to outcome (2).