Without a runner there is going to need to be a ‘leader’ of each line directing traffic a bit (the way Johnno used to do for us in defence). It raises an interesting question about who would be the leader of the forward line? It’s not obvious to me who that would be.
I would also like the AFL to limit interchanges until after goals. The bench was never designed for 90-odd players running onto the field semi-randomly during the game. Also, if midfielders know they can come off as soon as they are absolutely buggered, they will go hell-for-leather for that whole time. If they don’t know exactly when they’ll be able to get a rest, the average speed of players might drop a little, which I think would be a good thing.
My main concern is that one day someone is going to think they are in the clear, and get absolutely snotted by a bloke coming off the interchange bench.
