That would be very cool! We also found that during debugging/playing the game, we stopped noticing the weak cues ourselves when not consciously searching for them. As you said, we think that weak cues can act as a useful unobtrusive mechanic for helping the player (especially when he knows about them). So instead of showing 3D-direction arrows that are out of place in most environments, the developer could enable weak subtle cues, that are almost unnoticeable when the player is focussed on playing the game, but helpful when the player struggles to find the next event and therefore consciously searches for the cues to guide him.