Elijah and Moses appeared to Jesus during the transfiguration. Who better to appear and preach to the unbelieving World? I heard Greg Laurie mention the "Angels Preaching" to mean possible angels preaching in all those areas we can't get to. We all have ideas, I can't the Two Witnesses would be part of a group by corrupt men, why would Jehovah use unclean men like Russell and Rutherford and Knorr to preach his Holy Word?
The Two Witnesses will be something special, people with irreproachable names, not part of the Crazy 8 Gang of Bethel!
Lars58 might be right too, time will tell!