Based on a quite quick read, I have to say that discovering even the least hints about this new menace was enough thrilling for me. Especially, I would be much interested in that mysterious disappearance of ships, which sort of infers that something is indeed at work in the shadows. Just like the beginning of Sauron's poisonous influence on the woods surrounding the ruined fortress. A pivotal prelude to start with. And, apart from scarcity of broader and more detailed information, I found the hints that were provided quite revealing, in that they indicate the seeds of sedition being sowed in the supposedly peaceful Fourth Age.
And I obviously agree, when we refer to the never-ending character of this universe. One might have said that history could be halted just after the banishment of Morgoth from the ways of Arda. There has been, though, plenty to write about the future happenings of the Second and Third Age. Therefore, even at a smaller (lesser) extent, I'm more than sure that something might be written even for the Fourth Age of Arda. Not so much of a challenge for whom boasts a mastery of story-telling.