I would have certainly used such a feature many times :) What I mean exactly is a button like Move, Rotate, & IK which could be used to reset the values of a selected joint. It would make it much easier sometimes to start from scratch than try to move a limb that is in some kind of a dead lock state (does not want to move in any direction). As a second thought, it should ask "Are you sure?" - since I'm always hitting the wrong buttons by accident :)