"Wherever the corpse is, there the vultures will gather"
This has had various interpretations down through the ages. But one must notice the context of the statement. Jesus has been asked where He would return. And He is getting to this answer. He says don't be fooled if they say that Christ is in the wilderness or in the inner rooms. He won't be there. Jesus says that just as lighting comes from the east to the west so will the coming of the Son of Man be. Then He quotes this saying.
One gets the impression that this may have been a proverbial saying that came to mean something different than the words that were used. It is true that wherever the corpse is, there the vultures will gather; but it seems to be more of a saying which means real vultures won't have to be told where the corpse is. If it is a dead thing, vultures know if it's real.
This seems to be the intent of the saying. It does not mean that there will be lots of dead bodies or that Jesus will be judging lots of people. Instead it seems to be a "You don't have to be told where the dead body is if you're a vulture" truth. In other words, if you are a Christian you will know where Christ really is. In John 10, Jesus says something similar, “My sheep hear my voice and another they will not follow.”
This seems to be a saying in the same way that we have sayings or truisms that point to a generally understood truth underlying the statement like "penny for your thoughts" or "that's the long and short of it" or "if the horse is dead, dismount" or "every dog will have his day" or "he doesn't have enough sense to come in out of the rain" or "these are the dog days of summer" or "the rule of thumb is."