Having said the above, let me talk about what I think the GB have definitely got wrong.
Matthew 24:45–47 is a major example for starters - perhaps the biggest - where I think the GB have overreached themselves.
Could the "slave" be illustrative of a group? Perhaps, but that does not mean it's them.
The verses say "the master" appoints the slave - not that the slave effectively appoints themself, which is what the GB has done, especially in recent years by displacing the rest of who they consider the 144,000.
Also, the slave is said to be looking after Jesus' "household", and is contrasted with a possible "evil slave" who would "beat his fellow slaves". The more the GB has been dogmatic and applied rigid rules and punishments over the years, the more they have separated themselves from that definition by default and tended to look like the latter description of an "evil slave" (which of course they themselves dismiss as not an option).
Importantly, the parable of the faithful slave has something else in common with many others from Jesus which the GB has ignored: the point in time when the "Master" appears.
- In the parable of the virgins, the master/groom appears just before the wedding and goes into the feast.
- In the parable of the sheep and goats, the master appears just before judgement to begin separating the two groups.
- In the parable of the talents, the master appears at the end to reward each slave for how they've used the talents.
What's the common factor? That the master/groom arrives, coming from a long distance, near the end of events to render judgement/outcome.
So it's far more likely that in the FDS parable too, Jesus is talking about coming at the end of the system just before Armageddon to assess those claiming to represent him and reward faithful servants, not at some time that is now over 100 years ago! That faithful "slave", whether an individual or a group, is then appointed to feed the people after that time forward.
There are a wealth of scriptural reasons why the GB interpretation of the parable of the FDS is wrong. Another could be that it implies Jesus is going to wholly reward a single specific organisation, but the scriptures suggest that Jesus will take faithful ones from wherever he finds them, not just one single group. At Matthew 13, for example, the wheat are "scattered" among the weeds and indistinguishable until the "harvest". If the JW Org alone was the only one standing out, that would contradict those words.