I am a postmillennial, and postmils like to speculate about the long view.  What is the church and world going to be like after another several millennia of evangelism, baptism, teaching, discipline, Eucharistic merriment?  My answers to that tend to be:

1) The state of things, over time and in time, will be recognizably as the prophets predict: Zion will be raised as the chief of the mountains, nations will beat tanks into tractors, chemical weapons into fertilizers (napalm - a sign of millennial bliss?), peoples from the four corners will be eager to hear the instruction of Jesus, and will live by it.

Yet, some qualifications are in order, so my other answers to the question, “what will the church and world look like in a thousand years?” are

2) Who knows? We can’t determine this with the infantile categories we’ve got now.  We’re only beginning to understand Scripture, or the world.

3) The problem is not only infantile categories, but historical contingencies.  No postmil in 1500 could have had the slightest inkling of the state of the church in 2010.

4) There won’t be any one system.  There never will be.  The church will not look the same everywhere.  Assuming there’s still a China, I expect Chinese Christians to worship in Chinese; mutatis mutandis , global dittos.  Not only cultural differences, but historical contingencies will shape things differently in different places.  A church that has a half-century conflict about the genealogies of 1 Chronicles (Christians can fight about anything ) is going to be a different place than a church that had a century-long battle over the chapter numbering in Isaiah.

5) As a postmil, I’m not committed to saying that all unbelievers will be converted, or that every nation will be completely and absolutely conformed to the word of Christ.  All will be hugely more sanctified than now; but even then, some more, some less.

6) We’re in the millennium now, and so the messiness is not a “pre-golden age” reality but a “golden age” reality.  We’re not waiting for another epoch of redemptive history, in which all the rough edges are going to be smoothed.  We’re in the last age before the consummation already.  Many rough edges will be smoothed over time; some more, some less.

7) Despite our ignorance about the future, and the clumsiness of our categories, and our childish understanding of Scripture and the world, and our lack of faithfulness, it’s useful to speculate on what the future will look like.  So long as we take our limitations well into account.

8) Most crucially (in the etymological sense): The church will never, ever, ever, ever, ever, ever, ever transcend the cross.  Whatever we say about “latter day glory,” we can’t forget that we follow a crucified and risen Savior to the end.