We have to understand the motivation behind all these changes.
In the case of Charles Taze Russell, there was actually, from the part of the Bible Students a deep loyalty and almost idolatry to the man, who was considered a messenger of God and the "Faithful and Wise Servant."
When Rutherford, by shady means, ascends to the presidency of the Watchtower, begins to undermine this "image" and reverse some of the teachings of Russell, even calling some of them "teachings of Satan" (ex. the pyramid of Gizé). These changes are gradual and slow, but effective in the annulment and the importance given to Russell.
Is Rutherford himself, which classifies the Watchtower Society and its directors, as acting as "slave" and not Russell. The motivation behind this was obviously the envy of the cult of personality around Russell. Rutherford wanted the glory to him, and always be in constant comparison with its former President, was frustrating for him.
With respect to the motivation of the current CG, for me is the same. If indeed they are producing spiritual nourishment and are solely responsible for the global leadership to JW, why share the glory and this position with other thousands (which every year increased in number) and probably begin to challenge some the policies and doctrines of the Watchtower?
Being only the CG, the "Faithful and Discreet Slave", no one can challenge its decisions, even claiming to belong to the anointed class!
Thus, this group of men has no accountability to anyone and holds absolute power in a practical and moral standpoint.
No "anointed" can raise questions and his voice, saying that he too has a right given by Christ to rule. This right was denied definitely!
Another master stroke on the part of the Organization, in order to silence opposition, as did Rutherford in the past.