It's vaguely been done but it's a shame that we have MMOs in 3D environments these days and nobody really adds in platforming and puzzles to get through dungeons.

I'd like to see dungeons that don't have time restraints and allow for players to solve through finding clues in the world and in the dungeons themselves.

Figure out how to pass through a dungeon whether it be use special classes and skills, popping the right switches...triggering traps. Heck that big round rock rolling down to sandwich you chase is sorta fun. Should totally see more of that sort of stuff.

I think the tendency is for many games to focus in on just enter area find big boss and kill but you can create a great story line just through puzzled areas that require some thought and exploration.