One notes that the author refers to himself as “John,” but not in such a way as to point clearly to John the son of Zebedee or to the anonymous beloved disciple in the gospel of John. The name John (Gk Ioannes; Heb Yohanan) was common among Jews from the Exile onward and among the early Christians (Swete 1909: clxxv). The author of Revelation never refers to himself as an apostle or disciple of the Lord. In the vision of the new Jerusalem, the twelve names of the twelve apostles of the Lamb are seen inscribed on the twelve foundations of the wall around the city (21:14). The implication is that the Church in the author’s time prefigures the new Jerusalem or that it is the earthly counterpart of the heavenly Jerusalem. The interpretation of the foundations of the wall of the city as the twelve apostles is characteristic of a time in which the age of the apostles is past. It is unlikely that a living apostle would speak in such a way. Rev 21:14 has more in common with the post-Pauline Eph 2:20 than with Paul’s own remarks in 1 Cor 3:10–15. The conclusion that best fits the evidence is that the author of Revelation is a man named John who is otherwise unknown to us (for a more detailed discussion, see Yarbro Collins 1984: 25–34).
The historical quest for the identity of the author of Revelation has yielded primarily negative results. A more fruitful line of research has been the attempt to discern the social identity of the author. Considerable research has been done on the relation of the author and his work to the phenomenon of early Christian prophecy (Nikolainen 1968; Hill 1971–72; Müller 1976; Schüssler Fiorenza 1985: 133–56; Aune 1981; Yarbro Collins 1984: 34–49). Most scholars who have written on early Christian prophecy have distinguished community, congregational, or church prophets from wandering prophets. The primary evidence for community prophets is 1 Corinthians 11 and 14. The primary evidence for wandering prophets is the Didache. The community prophets are thought of as permanent, settled members of a particular Christian congregation. Wandering prophets are generally defined as translocal leaders, who traveled from place to place, proclaiming their teaching or the revelations they had received. This is a useful distinction but should not be pressed too far, given the great mobility of persons, especially of the nonrural population, that characterized the early empire. At least two types of wandering or itinerant Christian prophets may be distinguished: (1) the prophet who traveled to a particular place to execute a divine commission (Agabus in Acts 11:27–30 and 21:10–14; Hermas in The Shepherd of Hermas); (2) prophets whose wandering was an enactment of the ascetic values of homelessness, lack of family ties, and the rejection of wealth and possessions (Did. 11–13; prophets of the community reflected in the Synoptic Sayings source [Q]; Peregrinus in Lucian’s The Passing of Peregrinus [Aune 1981: 18–19, 29]).
In particular, note the beginning of the second paragraph: "[t]he historical quest for the identity of the author of Revelation has yielded primarily negative results." I haven't seen any recent arguments that would contradict this judgment.
UPDATE: Alan had posted an extensive presentation of external arguments for Johannine authorship here. I hope to take a closer look at these in due course. Check them out!