To be a KPF in the AFL, you need to take strong contested marks and have to have the confidence to take a shot at goal from 50 or anywhere inside 50. Not just dish of to someone under pressure, because you might miss.
Millers hasn't got a big enough presence inside the forward 50, opposition teams don't fear coming up againist him.
Millers gone for mine, he had plenty of time to take ownership of the forward line, but hasn't.