The Greek used in Revelation is so poor and so against the grammar of the Koine Greek language that it is been said that a greek person from the first century could not understand it propely. It is full of hebraism or aramaims. The greek of the Gospel of John and John's letters has nothing in common with Revelation semitic-greek ( just for coining a name for whatever language is that). The writer was not John for sure or John did not pen the Gospel and the letters or John did not pen any of those and the writers are differents. Even Martin Luther wanted to take it out of the cannon of the NT for condifering it worthless.