How could "the faithful and discreet slave" have been interpreting things properly? According to current WT doctrine, the people who thought they were "the faithful and discreet slave" from Russell's day until just a few years ago were wrong.
Most of my life, the organization taught that the FDS was all of the "anointed remnant." "New light" says only the GB is the FDS.
If they were wrong about who the FDS is (and that's a major and distinctive teaching of the WT religion), how could they get anything else right?
Of course, the whole FDS teaching is a misinterpretation turning a parable into a prophecy anyway.