I noticed this a while ago in the sword of Crota mission, that after using the sword your look sensitivity isn't reduced while sprinting for some reason. I didn't figure it was a big deal since you only have a short while at the end of that mission, but now with the sword public events and the sword being in the DLC this may be more important now. I did a patrol and got the sword and then had the normal look sensitivity while sprinting afterwards the whole patrol time, although it did not carry on after leaving the patrol.