The world translated “world” is not kosmos but aion which means “age”.
Some of what is forgotten is this part:
"45 “Who then is the faithful and sensible slave whom his [
aj]master put in charge of his household slaves, to give them their food at the proper time? 46 Blessed is that slave whom his [
ak]master finds so doing when he comes. 47 Truly I say to you that he will put him in charge of all his possessions. 48 But if that evil slave says in his heart, ‘My [
al]master [
am]is not coming for a long time,’ 49 and he begins to beat his fellow slaves, and he eats and drinks with those habitually drunk; 50
then the [
an]master of that slave will come on a day that he does not expect, and at an hour that he does not know, 51 and he will [
ao]cut him in two and assign [
ap]him a place with the hypocrites; in that place there will be weeping and gnashing of teeth."
So, what needs to happen before Jesus returns? I will answer the question to make it fair. Nothing. Jesus could com ---line disconnected
(sorry, I just felt like being funny.) For pre-millennialists, there are no prophecies left to be fulfilled. We are in a period of God's mercy, as Peter speaks about. God is not slack concerning his promise, but does not wish that any of the elect, any of his adopted children to perish. This is why we are told to watch and wait. It is also the reason for the parable above. We should be occupied with God's business, not screwing around with the world. Not joining in with those drinking and making merry in the days of Noah. Judgment and destruction are swift.