But looking at this more closely, what does this mean? The ultimate reward for a person is to be in the company of God. How in the world can one have levels of being in the company of God?
The works that are tested in fire are that of the individual, sure. But the works are then judged by Christ. Matthew 25 is quite explicit in the three Judgement parables.
Dante and much popular Catholic speculation has graduated levels of heaven. In Dante's book it was modeled off of the planets.
And the nine circles of hell, as well. There is really no compelling theological argument to either speculation. Especially if one believes that being in the company of God is the ultimate reward and being deprived of the company of God the ultimate torture.
You are correct in that is the current sentiment is most of Western Christianity, but a quick tour of many old churches (in Europe especially) and a review of much of the works of popular piety both Catholic and Lutheran reveal that wasn't always the case. Even today there are many who because of various private revelations will take issue with your statements. My mother in law (a devout Catholic) has many books filled with various visions of saints who saw hell and heaven, and lets just say the former is not just separation
But, getting down to the basics, you are right. Even the street sweeper in Heaven is a more wonderful thing than anything down here (assuming of course Heaven needs a street sweeper). We can't really know the heights of heaven or the depths of hell in our current state. Some may have had a partial vision of either, but after the age of the Apostles, few will claim that such visions or revelations are universally binding (for instance neither the Lutheran's or Catholic's view any private revelation as capable of being binding).