It's a difficult topic. I agree with your first statement, that there will be more people in heaven than we might expect, but I also believe that our eternal fate is determined by the choices we made in this life. Regarding those who never came to a full revelation of Jesus Christ, it can be said that at some point in their life, they chose good over evil or evil over good and many have a relationship with a God that they have yet to put a face on, and some reject such a relationship both never gaining a full understanding of the gospel. But for those who reject the love of God, there is no further chance after death, that must be made clear. If it were an issue of mental assent to the timeless truth of the gospel, then I understand why many people may never reach that point. But everyone who has lived has encountered the grace of God and responded to it or rejected it. This beneath the surface understanding of God's law is spoken of in Romans 1, the inner witness that woos people into a relationship with God.
But scripture informs us that "it is appointed for man once to die, then comes the judgement". This means after death we will be judged by the choices we made. I don't think the Bible can be any more clear on that matter.
yes, after death comes judgment from god but judgment doesn't necessarly mean damnation
Just remember God knows every heart; better than we know our own, and that itself explains where we will live eternally; also if I may add, if we are not to accept Christ as he came for us, to save us, and still be with God, then wouldn't that be calling the Most perfect and true and Mighty God...A Liar???