I brought this up completely spontaneously in the chat feed today, but I think it would be really great to get an indepth video interview with Robyn Miller and Richard Vander Wende, the two co-directors for Riven.
It was Robyn's story that became the basis for Riven and Richard Vander Wende was the outsider catalyst who helped shape the game into the classic it is today (along with shaping Cyan's modern artistic vision post-Myst). Robyn set the tone for the world along with composing the music and creating the characters while Richard added the strong element of visual storytelling and layering in the puzzles + environments + visuals.
He was the one who made Riven so creepy, creating the design for Tay and much of the more alien look of the game. He also was the one responsible for tying all the visuals into the primary antagonist, Gehn, telling a character portrait through the environment itself.
Because of this partnership, both men have become lifelong friends and have collaborated on occasion since then. (I'm not sure, but I sense Robyn's partner may be Richard VW for the www.nestingdollsimages.tumblr.com game. I really really hope it is him though.)
It would be interesting to hear them talk about their creative vision behind the game and how they moved away from Myst's aesthetic and storytelling into the much more nuanced approach of Riven. I want to hear what they have to say about how they blended everything together so well in the end and how Riven has held up 20 years later as a classic of videogame history.