I wasn't going to use this idea, as It just came to me today, and I really don't have interest in putting aside the ages I'm working on to start a new one again. So here it is: The Star Fissure is a link to Earth. This is established canon. The Stranger got back from Earth by falling through the fissure in Riven, during its collapse, along with the Telescope and large Moiety dagger. And our arrival at the Cleft after completing Yeesha's Journey.
And today, while reading through the canon history of Myst, i remembered a very important detail that had escaped me until today. Gehn used to use the Star fissure for experiments. He'd throw the Rivenese into the fissure as part of these experiments. Now what if, since the Fissure is a semi-stable link to Earth. These Rivenese actually survived. The idea I had was for a story chronicling a Riven Man/Woman's experiences after falling through the Fissure and arriving here on Earth. I'm not sure how this would fit into someone's age. my thoughts were that one of the explorers, after visiting D'ni, would do some research into the cultures surrounding the Cleft at the time after Atrus trapped Gehn on Riven, and learn of ancient indian, or spaniard legend, of a strange man/woman who was found wandering the desert etc.
I just thought i'd throw that out there, and see if anyone wanted to use it in an age journal or something.