The 'judgment' will be a pronouncing of the verdict- but it will be accompanied, it seems, by an explanation. This is so that God's Name may be glorified, and also so that those who observe the process will do likewise. The Angels glorify God as they behold His true and righteous judgments in the earth; and so will all who behold the final judgment (Rev. 16:5,7). According to Lk. 19:23, the Lord will shew the unworthy how they could have entered the Kingdom. This is after the pattern of rejected Adam and Eve having the way to the tree of life clearly shown to them after their rejection (Gen. 3:23,24). Again, notice how the judgment is for the education of those judged and those who witness it. He will shew them how they should have given their talent, the basic Gospel, to others, and therefore gained some interest. This has to be connected with the well known prohibition on lending money to fellow Israelites for usury; usury could only be received from Gentiles (Dt. 23:20). Surely the Lord is implying that at the least this person could have shared the Gospel with others, especially (in a Jewish context) the Gentile world. This would have at least brought some usury for the Lord. This would suggest that issues such as apathy in preaching, especially the unwillingness of the Jewish believers to share their hope with the Gentiles, will be raised by the Lord during the judgment process. Of course, the Lord hadn't told the servant (in the story) to lend the money to Gentiles; he was expected to use his initiative. The overall picture of the story is that at least the man should have done something!
Alternatively, it could be that we are intended to understand that the Lord would even have accepted him if he lent money on usury, something which the Law condemned; if he'd have done something, even if it involved breaking some aspects of God's will... Instead, his attitude was that he had been given the talent of the Gospel, and he saw his duty as to just keep hold on it. He was angry that the Lord should even suggest he ought to have done anything else! We really must watch for this attitude in ourselves. He justifies himself by saying that he has "kept" the money (Lk. 19:20), using the word elsewhere used about the need to keep or hold on to the doctrines of the One Faith (1 Tim. 1:19; 3:9; 2 Tim. 1:13; Rev. 6:9). He had done this, he had held on, he hadn't left the faith. And he thought this was enough to bring him to the Kingdom. Sadly, our understanding of spirituality has almost glorified this very attitude. Any who show initiative have been seen as mavericks, as likely to go wrong. The emphasis has been on holding on to basic doctrine, marking your Bible with it, attending weekly meetings about it (even if you snooze through them), regularly attending...And, son, you won't go far wrong. The Lord, in designing this parable as he did, had exactly this sort of complacency in mind.
It may well be that the rejected are each given a punishment appropriate to their errors (1), again showing forth the principle of the judgment manifesting God's Name, and in keeping with different degrees of punishment at the judgment (Lk. 12:47,48). Because Israel said "No; for we will flee upon horses [and not need Yahweh's protection]; therefore shall ye flee [in the condemnation process]: and, We will ride upon the swift; therefore shall they that pursue you be swift" (Is. 30:16). Because Israel thought they could flee God's judgments on swift horses, therefore their judgment came to them on swift horses. If Israel broke through to gaze, Yahweh would break through upon them (Ex. 19:24); their punishment would be appropriate to their sin. Under the Law, every sin received an appropriate judgment, and this anticipates the final meting out of punishment at the last day (Heb. 2:2,3). Even in this life, homosexuals receive a punishment for their sin which is an appropriate recompense. Adam and Eve were punished in ways appropriate to their individual failures. The lazy servant was punished out of his own mouth (Lk. 19:22); and even in Job's time, this principle of Divine condemnation was known (Job 9:20; 15:6). The Judaizers too were to have an "end [that] will correspond to their deeds" (2 Cor. 11:14,15 RSV).
Then, the rejected will finally see their good works in context. They will realize how little works really meant. The faithful already knew that- for they objected when the Lord told them all the good things they had done. The list of works in Mt. 25:35,36 include the following: giving food to the hungry, clothes to the naked, a bed to the homeless, help to the sick. Yet these are the very things which Job claims he had done , when he clears himself from all his accusers (Job 31:17-20). But the voice in the whirlwind soon reduced him to realize "I am vile"; all his good works became as filthy rags before the supremity of salvation by grace alone. The connection with the parable isn't merely incidental. Surely the Lord is saying that the self-righteous in the ecclesia may seem as righteous as Job was before his conversion; but they must either in this life realize the totality of grace, or the whirlwind of judgment condemnation will reduce them to the same realization. Job seems to oscillate between believing and not believing in the resurrection (consider Job 14:7-15). At the end, Job confesses he has not spoken the right things; and Yahweh then says that he has only spoken that which was right. The friends likewise said some true things and some false things; and yet because they did not repent, their bad words were remembered against them. The final revealing of Yahweh in Job was some kind of judgment day for all concerned. Job, the righteous, had only his good deeds and words remembered; whereas the wicked friends had only their bad words remembered.
In passing. The Lord foretells the spiritual culture which He will show even to the rejected, when He mentions how He will call the rejected "friend" (Mt. 22:12), using the same word as He used about Judas (Mt. 26:50). Vine describes it as a word meaning "comrade, companion, a term of kindly address expressing comradeship". If this is how the Lord will address those who have crucified Him afresh- surely there is hope, abundant hope, for us. The Lord Jesus will be ashamed of the rejected when He comes in the glory of the Father (Mk. 8:38). There is a telling juxtaposition of ideas here- shame and glory. Amidst the utter glory of the Father's throne, surrounded by Angels, the Lord will be sitting there with eyes downwards in shame as the rejected stand before Him and walk away. The Proverbs speak of how shame is to be the ultimate end of the wicked, and glory the end of the righteous. Yet it is the rejected who go away "into shame". They will be "ashamed before him at his coming". Yet the Lord will so feel for even the rejected, that He feels for them and reflects their feelings. This is no stern-faced judge chasing away those He is angry with. This is a window into the Lord's ineffable love and feelings even for those for whom it truly is too late, for whom the way to the tree of life is now barred.
(1) Bro Mark Vincent has pointed out the appropriateness of God's condemnation of the Babel builders. Their "go to, let us make brick" was matched by His "Go to, let us go down...". They wanted to reach God; but He came down to them in judgment. They feared being scattered; and this is what therefore was done to them. They 'made brick', using a Hebrew root L-B-N. But God 'confounded' their language, using a Hebrew word 'N-B-L'. He somehow confused them and gave them a punishment in terms appropriate to their sin, just as AIDS is an appropriate judgment for homosexuals (although this isn't to say that AIDS only afflicts the immoral).