Fr. Corbett proposed a simple, three-part division to the Book of Revelation: the exhortation to the Seven Churches (chapters 1-3); God's judgment against the Great City (chapters 4-18); and the establishment of the heavenly City (chapters 19-22).
From each section, he gave a key verse. If "God wins!" is too brief a summary for the entire Book, you might try this:
I also saw the holy city, a new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband.
Fr. Corbett also pointed out how liturgical Revelation is. The third sentence of the book, "Blessed is the one who reads aloud and blessed are those who listen.... [1:3]," suggests it was written with the intent that it be read during Christian religious services.
John goes on to write, "I was caught up in spirit on the Lord's day [v. 10]"; this is just the sort of thing that happens at a charismatic prayer meeting. He sees "seven gold lampstands and in the midst of the lampstands one like a son of man, wearing an ankle-length robe, with a gold sash around his chest. [vv 12-13]" Here Christ is dressed as High Priest, standing in the midst of His churches (the lampstands; see v. 20).
The liturgical signs continue through the whole book, all the way to the final, "Come, Lord Jesus," which the NAB notes is a liturgical refrain.
(I'm not really doing justice to Fr. Corbett's ideas or presentation, but that's what you get for not coming to his talk yourself.)