The thing I remember most about sierra games are the dead ends.
This usually happens when you got to a certain place in the game and you can't move on no matter what you do. Then, when you look at a walkthrough you see you forgot to pick up a certain item and you need to restore or restart to get to that point in the game.
This is something both lucasarts and telltale (till now) avoided.
But if they're remaking king's quest what will happen?
I prefer it if they will continue to avoid those dead ends. I didn't like them - they seemed so unfair, it was the main reason i preferred lucasarts games to sierra.