I've always imagined D&D like fantasy campaigns being translated over to the PC in video game form, but not just like Baldur's Gate, the Pathfinder games or DOS2 (or any other CRPG) - no, I'm thinking more along the line of a super smart DM/GM AI capable of learning world building with randomly generated worlds and stories.
I'm not talking about random generation in the sense that we know it (some variation between predefined worlds) - I'm talking about an AI that has the ability to learn and evolve its creativity, making endless worlds for you to campaign in - imagine if every single AI generated world/lore/story was as dynamic, rich and creative as hand-crafted experiences (think Dwarf Fortress world generation, but even more random in the way of its structure, its cultures and races inhabiting it).
That would effectively mean infinite possibilities and it would probably be a game that you could, quite literally, play forever and never get bored of - I'm not sure it would even be classified as a singular game, since at that point it's basically just a "CRPG generator", a "PnP RPG generator" or just a "world building and adventure simulator" using AI technology.
Just imagine, every time you start a campaign in that game, you would get your own personal story, that no one in a billion years would experience again (literally).
Of course, we'll never live to see this kind of game, and it's not far fetched to say that a concept that advanced won't ever actually be turned into reality.