Grissom wanted to know what the problem is. There are actually multiple problems with the JW view:
First: How can you be appointed by Christ over all his belongings and not even know it?
Jesus ostensibly returns in 1914, conducts his inspection and subsequently appoints the faithful Bible Students over all his belongings. --Only they don't know it because they don't know the Faithful and Wise Steward is a "class" of faithful Christians. They think the Faithful and Wise Steward was a single individual --Charles Taze Russell.
Fast forward 10 years and they still don't know of their appointment, because they still think the individual was Russell. It was not until 1928 that they decided that the Faithful and Wise Steward was composed of individual Christians.
Second: Under what circumstances is it permissible for a slave of Christ to declare himself faithful?
Since Jesus did not make this alleged appointment in any tangible fashion, (As evidenced by the 10 year lacunae) then the status of Faithful and Discreet is entirely self-proclaimed. In other words, Jesus did not declare the slave righteous, the slave has declared himself righteous. Doesn't the judging of Christians as faithful or not more properly fall under Jesus' perview?
Ignoring this problem creates a ludicrous circularity in Witness reasoning because the claim becomes in effect, the authority to make the claim in a snake swallowing his own tail sort of fashion.
IOW JW's know that their Governing Body compose the mouthpiece of the Slave because that selfsame group has told them so. Conversely, JW's know that they can trust what their Governing Body says because they compose the mouthpiece of the Slave.
Third: Jesus never actually said what the outcome of the slave would be. The slave could either be rewarded or punished based upon what he was found doing at Christ's return. This makes the story a parable, not a prophecy The Witnesses treat it as the latter because they assume the favorable outcome. However Jesus actually said no such thing.
