The personality that these assessments is looking out for is an extrovert teamplayer ... I'm not quite sure whether leadership qualities are required. In a multi-crew environment, a co-pilot has to be able to have the confidence to alert a captain if they have done something wrong or made a possibly incorrect decision. The captain has to have the humility to accept that from a junior as well.
Leadership tends to imply an hierarchical situation of leader/follower and this is not desirable in a cockpit.
Obviously, the student has to learn to accept criticism. So when concerns were expressed over leadership qualities, it might be that there was too much leadership and not enough teamplying. I'm afraid ANW1988, that I am getting the impression that no-one can tell you anything because you already know it.
Cheers
Whirls