I don’t usually spend my time going after preterist interpretations of scripture (mainly because I don’t have enough time and energy to do all the other projects I want to do )–but I honestly don’t think such an exegesis holds up as an argument for an entirely fulfilled prophecy without a larger and greater fulfillment on the way.
1.1.) The scope of this, as with the tares parable which precedes it (and which this, as Oxy rightly says, is a parallel restatement of), is much larger than Jerusalem and its environs. “The field is the world”; so is the sea. The fish gathered are of every kind.
1.2.) Relatedly, while the quote from Ezekiel does specifically limit itself to Jerusalem, there is nothing in either of the parables to specifically indicate limitation to Jerusalem and its locality.
2.) Angels didn’t come to pick up all the sons of the evil (Jewish or otherwise) out of the kingdom of God and put them into Jerusalem to be zorched by the Romans. Nor did angels come to take the wicked out of Jerusalem leaving the righteous in there, in order to cast the wicked into… Jerusalem?? (Or is that supposed to be Gehenna valley now?) Those things did not even figuratively happen.
3.) The concept of multiple fulfillment cannot be excised from such a prophecy, because the Ezekiel prophecy was in fact already quite fulfilled with the original overthrow of Jerusalem! If that prophecy was also supposed to count for the overthrow of Jerusalem by the Romans (although frankly I doubt it), then this prophecy can also just as easily (and on better ground thanks to the scope) be supposed to count for some upcoming future judgment that hasn’t happened yet.
4.) As Israel fares, so fares the world under God. This frequent scriptural principle cannot be ignored by universalists (of all people!–seeing as we build our scriptural case on this frequent principle). The language of the tare and dragnet prophecies fit this extension of the scope, which clearly hasn’t been fulfilled yet.
No doubt the Ezekiel passage features furnace language applied to the (pre-Christian!) overthrow of Jerusalem. But a limited application of language to Jerusalem and/or Israel in one passage does not mean all future and/or other useage of such language must also apply to Jerusalem and/or Israel. The prophets used much the same language of reprobation for both Israel and Babylon, including the striking parallel of each of them being a whorish sorceress who claimed divine glory for herself and refused to recognize that she was a widow. As Jerusalem fared, so did Babylon eventually. (For that matter as Israel fared, so did Judah and Jerusalem eventually!)
5.) The tare prophecy references Daniel 12:3, the context of which also involves the rescue of Daniel’s people (or at least of everyone written in the book) from the depredations of a schemer who will arise in a time of peace to take power even though the honor of kinghood has not been conferred on him, and after instigating war with kingdoms north and south of Palestine will set up the abomination of desolation in the sanctuary doing away with the regular sacrifices (i.e. will set himself up as God’s presence in the Temple holy of holies). At that time, there will be a resurrection of many (or all?) people, some to eonian life and others to disgrace and eonian abhorrence. It would be highly optimistic even to say that “the righteous shone” henceforth “like the brightness of the sun” after the fall of Jerusalem–possibly the gigantic moral failures of Christendom in the thousands of years afterward still count as that–but none of these things happened in the fall of Jerusalem in 70 CE. Nevertheless Daniel 12, and those two prophecies, are looking forward to the time of the final coming of the Son of Man in judgment and salvation.
It would be better, I think, to accept the scope of the parables as a warning for more than just Jerusalem to come, even though in other sayings Jesus is warning Jerusalem specifically–but neither the broad nor the focused warnings obviate each other. As the focused warning came to pass, so should we expect the broad warnings. The stated local scope of furnace imagery in one warning does not obviate the stated broad scope of furnace imagery in another warning. A hurricane that stomps an island in the eastern Carribbean may take a while to get to continental North America, and warnings for the local incident may sound similar (for obvious reasons) to warnings for a broad region; but to claim that since the island was flattened the coast is therefore safe from broad warnings (so to speak) is not good exegesis.
I think there are better interpretations of the parables than that.