I don't know what line this would fit into but I think it would be cool to have an ability that would allow someone to essentially become a free-moving camera for a period of time. Let me explain...
A player could activate the ability and be unable to do damage as well as take damage or be affected by cc/status affects for a limited amount of time. This can only be activated out of combat to remove exploiting it simply run out of an active fight. I suppose it could still be exploited if someone was being approached by an enemy in a PVP zone.
Regardless of the mechanics, I think it would be awesome to allow someone to capture first person footage from the front lines of both PvE and PVP combat without fear of insta-death. It would make for great video uploads that would help promote the game.
The only issue is that I can't think of a way that would not open up a potential exploit. Maybe just allowing someone to log on as a spectator would do the trick.