[mrLOL]

I've never heard of A Mind Forever Voyaging, Shenmue, Omicron, Simon the Sorcerer 3D and Magic Turn but will definintely check out let's plays of next time I'm on broadband, thanks.

Ever since GTA: Vice City I thought how silly it was that people were just using this open world concept to only make GTA clones like Mafia or Scarface or Saint's Row.

Yes exactly, when you play a open-world game like GTA you can hate the violance, the criminal attitude or some of the many flaws but it's very obvious that open-world is a winning concept, it just really takes advantage of what interactivity can actually achieve, and people love it and the profit shows it, yet whenever another company tries to take advantage of open-world all they do is steal the exact gta-concept with a minor twist (1940-era, play as cop, play as cartoon super-hero),
you would think that many genre's (incl. adventure-games) would be rushing to take advantage of that winning concept yet no such effort seems to be made.

some of the early AGI Sierra games felt very open world. The first King's Quest particularly.

I agree that some adventure-games has a open-world-feel, but at least IMO those games like King's Quest is very different from what I had in mind since that is just a 3-trials concept gone (perhaps overly) large, there's not really any open-world freedom other than doing the 3-trials in whichever order (& simultaniously) you like and wandering around aimlessly hoping that your exploration somehow makes you progress in any of those 3-trials.

If you think about it there are already several adventuregames that let the player have access to many different locations at once. Monkey Island 2 did this

I agree it very much depends on definition of "open-world" which is making this very complicated subject to discuss
I guess MI2 does not fit my description of true open-world, as it's just 3-trials, if you took 3 levels in Doom and changed them from being played in order into changing so that you can skip between them, then that's not really open-world IMO, as all you're doing is allowing you to play 3 missions simultaniously, but you're not really creating a open-world where exploration is meaningful since everything you do in this open-world-illusion is of direct relevance to any of your 3 tasks, if that makes sense.