I read the famous admonition of Henry Alford concerning the interpretation in Revelation 20 is worth repeating here:
As regards the text itself, no legitimate treatments of it will extort what is known as the spiritual interpretation now in fashion. If, in a passage where two resurrections are mentioned, where certain psychai ezesan ["souls came to life"] at the first, and the rest of the nekroi ezesan ["dead came to life"] only at the end of a specified period after the first, -- if in such a passage the first resurrection may be understood to mean spiritual rising with Christ, while the second means literal rising from the grave; -- then there is an end of all significance in language, and Scripture is wiped out as a definite testimony to anything. - Henry Alford, "Apocalypse of John" in The Greek New Testament, 4.732
I think Alford's criticism is a valid one. It is evident that an interpreter who doesn't believe in a millennial reign after the Second Coming and prior to the eternal state in Revelation 20 approaches the passage with preconceived notions and leaves with the same; he gains from the text "neither the exact sense nor the value."