So, are we all in agreement that the WTS is "not" the faithful and discreet slave as they claim to be? If so, then who really is?
No one is.
45 “Who then is the faithful and wise servant, whom the master has put in charge of the servants in his household to give them their food at the proper time? 46 It will be good for that servant whose master finds him doing so when he returns. 47 Truly I tell you, he will put him in charge of all his possessions. 48 But suppose that servant is wicked and says to himself, ‘My master is staying away a long time,’ 49 and he then begins to beat his fellow servants and to eat and drink with drunkards. 50 The master of that servant will come on a day when he does not expect him and at an hour he is not aware of. 51 He will cut him to pieces and assign him a place with the hypocrites, where there will be weeping and gnashing of teeth.
Who is the faithful and discreet slave of Matthew 24:45? Who is the wicked servant of Matthew 24:28? Notice the faithful and discreet slave of Matthew 24:45 is the same one in verse 48 - "But suppose that servant (faithful and wise) is wicked..."
So, Jesus was speaking an opportunity for Christians. Take care of your fellow servants and when Jesus returns he will put you in charge of all his possessions. Beat on your fellow Christians and Jesus will cut you to pieces.
In short, its a promise and a warning to Christians. Be Christlike or else. It is not a designated person or group.