And not the Uru Live/MMO sort of thing. Just good ol' single-player content. I wish they did that.

Well, URU Live, Until URU and MO:URU Live (through Gametap) don't fall under the MMO category i think, as the 'Massive' bit was never there ;)
And even if this is probably one of the very few online gaming experiences i'd be interested in, i agree . A great deal of the Myst atmosphere comes from the lonely exploration aspect, and as such, more single player content would be most welcome.