I don't know about URU, but in the early Myst games you're constantly on isolated, weird structures, either on an island or simply at sea. I could easily see a puzzle where you have to meddle with devices in each tower, travelling between them over walkways (and that particular setup is certainly everywhere in Myst). Just the vibe I got from it.
Yeah, I see what you're talking about. Reminiscent of This and maybe this.
I think it would belong more in Riven though, Gehns contraptions gave Riven a more industrial feel than Myst.
Edit: addressing walkways, underwater passages could be done. Walkways would work if they were made right. The walkways shown in the article fit the structure well but probably wouldn't work so well from a gameplay standpoint. There would be too much scout camping. A boat (similar to the one in the one large boat map with the smaller boat that circles it) could work, but I think underwater concrete passages would probably be the best aesthetically. Even the concrete passages could be a really cool addition given the right lighting. The whole thing looks much more surreal without visual connections.