Hard to choose the biggest change but apart from the changing doctrines, selling the properties and moving out of Brooklyn, laying off Bethelites, closing Branch offices and getting rid of the Special Pioneers etc was a significant indication of deep problems going on.
As far as them appointing themselves as the Faithful and Discreet Slave. I thought this is how they've viewed themselves since the C.T. Russell days. Didn't this idea come from his wife and she pushed her husband into reluctantly pursuing it?