Some of the issues with parsers and knowing what to type could be helped quite a bit if the text adventure interfaces had a bit more affordances. Making important objects bold is an easy one (unless you feel that determining the importance of objects is part of the puzzle). But if you break out of the linear-narrative approach there's a lot to do. Label exits with their destinations (if you have traveled there before). Use colors akin to blue/purple links to indicate history. Inventory doesn't need to be a command. If mapmaking isn't part of the challenge, then give people ways to move quickly (e.g., "go to throne room" could just find a path to the throne room based on your knowledge).