Here are a couple passages to consider when discussing this:
Matthew 19
30But many who are first will be last, and many who are last will be first.
And again:
Matthew 20
8"When evening came, the owner of the vineyard said to his foreman, 'Call the workers and pay them their wages, beginning with the last ones hired and going on to the first.'
9"The workers who were hired about the eleventh hour came and each received a denarius. 10So when those came who were hired first, they expected to receive more. But each one of them also received a denarius. 11When they received it, they began to grumble against the landowner. 12'These men who were hired last worked only one hour,' they said, 'and you have made them equal to us who have borne the burden of the work and the heat of the day.'
13"But he answered one of them, 'Friend, I am not being unfair to you. Didn't you agree to work for a denarius? 14Take your pay and go. I want to give the man who was hired last the same as I gave you. 15Don't I have the right to do what I want with my own money? Or are you envious because I am generous?'
16"So the last will be first, and the first will be last."
Perhaps the many who come from the east and the west will be the chosen plus the heathens and the wicked - Hitler, Bin Laden, etc. Perhaps all of the wicked will find their way into the kingdom even before the called, which will, of course, cast them into even more torment. I think of this passage:
John 9
7"Go," he told him, "wash in the Pool of Siloam" (this word means Sent). So the man went and washed, and came home seeing.
8His neighbors and those who had formerly seen him begging asked, "Isn't this the same man who used to sit and beg?"
...10"How then were your eyes opened?" they demanded.
It kind of reminds me of what the called might say if they saw Hitler in the kingdom while they themselves are still on the outside. "Isn't this Hitler, then man who slaughtered millions of people? How did his eyes become opened?"
Also remember from Ezekiel chapter 16. I won't post the whole thing here, but it basically talks about how Sodom will be restored before Jerusalem will be restored, because Jerusalem's sins were worse than Sodom's! So, if we take earthly Jerusalem to represent the called, then it does seem as though the heathen will enter the kingdom before the called. Remember another thing that Jesus said:
Matthew 10
14If anyone will not welcome you or listen to your words, shake the dust off your feet when you leave that home or town. 15I tell you the truth, it will be more bearable for Sodom and Gomorrah on the day of judgment than for that town.
So, perhaps the called, who will refuse to accept the truth about their belief in false doctrines and traditions of men, perhaps they will be judged in a manner that will prevent them from entering until after all of the most vile heathens.
So, if we keep in mind that the first will be last and the last will be first (the chosen humble themselves just as Christ did, therefore they are considered the last, while the called, full of self righteousness, exalt themselves over everyone and so they are considered first) it seems as though the order of kingdom entrance will be: Chosen, heathen, called.
Therefore, there will be many in the kingdom while the called are still looking in from the outside.
Just a thought.