I have no clue, you're right, but I can only listen to what the players say, and they say he is very good around the club. That's all the proof I need.
He's mates with half the squad, has mates in the media and is pretty much an institution. Not to mention the fact no player would ever say anything other than something positive about a team mate (especially a senior one) in public. What they say about his leadership skills means absolutely sod all.
I would bet a serious amount of cash that there is a good number of players in the squad that would be better off without him at the club. Players that would impose themselves a lot more to the benefit of the club. I'd also wager that the quality of the squad will improve if they have a captain that can hold them to standards of his own and lead by example.
So my question is, since Rooney has been out of the side, has anyone else shown any 'proper leadership qualities'?
You're talking about leadership on the field as if that's the only thing a captain has to do. For starters Herrera and Mata have both improve without Rooney in the side and have both imposed themselves far more.