This is part of a Castlevania: Lords of Shadow - Mirror of Fate interview from Pure Nintendo...
Chris Solis: Some may see too much backtracking as a usability issue. Do you think this note-taking feature is a way to both make it more accessible and keep that depth that you're looking for?
Dave Cox: Funny you should say that. I kind of agree with you. One thing we've done with the game is put in a teleport system. One thing we noticed with focus testing was that some players didn't want to backtrack. They just want to get through the game, enjoy the story, and that's it. I can totally respect that but a lot of players want to go back. That's why we put the teleport system in to make it easier for players who did want to go back but weren't really interested in exploring every nook and cranny.
And the note-taking system, again, is something to save time for players so that they can plan out what places they need to revisit. They can plan where they need to go instead of wandering aimlessly, thinking "Where do I go next?" Some people love to wander aimlessly. That's part of their experience and they enjoy that. If they want to do that, that's fine, but we need to give tools to players where they can play their way, whatever it may be. I think that's always important when you're making a game in development, that you allow players to play their way.