Keep in mind that the date of Revelation for many people is a loaded theologically driven issue. For those whose theology states that Revelation is about the destruction of Jerusalem, obviously it must be written before 70AD; for many who oppose this, there might be a tendency to advocate a later date to make it easier to defeat their opponents' theological reading (obviously, if it's written after 70AD, that reading is wholly incorrect).
I can't be too much help to you on this one. My academic interests have been with Paul and the synoptics. Most of the material on this with which I am familiar is from the 1800s, and I'm sure much more research has been done since then.