[NotReady]

All this is highly speculative.

I would never try to limit God, and if He has more to tell us, He will, but it would seem the canon is closed. The purpose of the Bible is primarily to tell us Who God is and who we are, to reveal what is necessary for salvation and why salvation is necessary. I don't see how further revelation would add to this, but if it is needed, God will do so.

As for immortality, we already have it. "The free gift of God is eternal life through Christ Jesus our Lord". But "It is appointed to men once to die and after that comes judgment". I don't think someone could prove they had achieved immortality in this life anyway, because it would take eternity to prove it. Even if all diseases were cured, there are many other ways to die. Again, this is very speculative and I don't believe mankind will even come close to eliminating death, but I'm all for science and medicine doing all they can towards that goal.

I don't know specifically how further communication would come, but I believe it would be clearly identifiable. It would not contradict what God has already said. This is why I think the Koran (that part of it not directly lifted from Scripture) and the Book of Morman are not God's Word. I suppose it would also tell us something important not already revealed, and I just don't have any idea what that would be.

There is a parable in the New Testament usually refered to as Lazarus and the rich man. The rich man has died and is in a place of suffering. He speaks to Abraham and asks him to warn his brothers of what he is experiencing. Abraham replies that they have Moses and the prophets and that is sufficient. That seems to indicate that in Old Testament times, nothing beyond what is written was necessary. The New Testament is obviously to identify Christ as the Messiah prophesied in the Old Testament, to end the dispensation of Israel, and give some guidance concerning the new age.

I'm not well versed in eschatology, but I believe the prophecies of both Old and New Testament concerning the next age include direct communication rather than written. Until then, I suspect God's Word for us will be the Bible, period. Even during the time of the apostles false gospels were being preached and mention was made of false prophets. This is also mentioned as something that will continue to happen up until the Second Coming. I see many "preachers" who claim to have visual revelations from Jesus, that Jesus audibly speaks to them, etc. I frankly dismiss all this because they invariably preach something contrary to Scripture. Cults are based on this kind of "revelation". Jim Jones and David Koresh come to mind.